Agilent Technologies N9917A, N9914A, N9918A, N9925A, N9926A User Manual

...

Download

Agilent FieldFox Analyzers

N9913A, N9914A

N9915A, N9916A, N9917A, N9918A

N9925A, N9926A, N9927A, N9928A

N9935A, N9936A, N9937A, N9938A

User’s Guide

Manufacturing Part Number: N9927–90001 Print Date: July 2, 2013

Supersedes: March 25, 2013 ©Agilent Technologies, Inc.

Warranty Statement

The material contained in this document is provided "as is," and is subject to being changed, without notice, in future editions. Further, to the maximum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a particular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or performance of this document or any information contained herein. Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the separate agreement will control.

DFARS/Restricted Rights Notice

If software is for use in the performance of a U.S. Government prime contract or subcontract, Software is delivered

and licensed as “Commercial computer software” as defined in DFAR 252.227–7014 (June 1995), or as a “commercial item” as defined in FAR 2.101(a) or as “Restricted computer software” as defined in FAR 52.227 –19

(June 1987) or any equivalent agency regulation or contract clause. Use, duplication or disclosure of Software is subject to Agilent Technologies’ standard commercial license terms, and non-DOD Departments and Agencies of the U.S. Government will receive no greater than Restricted Rights as defined in FAR 52.227–19(c)(1–2) (June

1987). U.S. Government users will receive no greater than Limited Rights as defined in FAR 52.227–14 (June 1987) or DFAR 252.227–7015 (b) (2) (November 1995), as applicable in any technical data.

Technology Licenses

The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.

Contacting Agilent

Assistance with test and measurements needs and information on finding a local Agilent office are available on the Web at: http://www.agilent.com/find/assist

If you do not have access to the Internet, please contact your Agilent field engineer.

In any correspondence or telephone conversation, refer to the Agilent product by its model number and full serial number. With this information, the Agilent representative can determine whether your product is still within its warranty period.

Safety and Regulatory Information

The safety and regulatory information pertaining to this product is located on page 188.

Where to Find the Latest Information

Documentation is updated periodically. For the latest information, please visit:

www.agilent.com/find/fieldfoxsupport

Software Updates

Is your product software up-to-date? Periodically, Agilent releases software updates to fix known defects and incorporate product enhancements. To search for software updates for your product, go to the Agilent Technical Support website at: http://www.agilent.com/find/TechSupport or www.agilent.com/find/fieldfoxsupport.

2 FieldFox User’s Guide

Elements of this product's Software use SharpZipLib as an "as provided" stand alone capability.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

To receive a copy of the GNU General Public License, write to the Free Software Foundation, Inc., 59 Temple Place

- Suite 330, Boston, MA 02111-1307, USA.

Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination.

As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

____________________________________________________________________________

Elements of this product's software use ANTLR.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

FieldFox User’s Guide 3

A.07.00 Firmware Release Updates ............................................... 7

Overview ...................................................................................................... 8

Models and Options ......................................................................... 8

Accessories ....................................................................................... 8

FieldFox Manuals, Software, and Supplemental Help ............... 9

Preparing for Initial Use of Your New FieldFox ................................... 10

Check the Shipment ....................................................................... 10

Meeting Power Requirements for the AC/DC Adapter ........... 10

Install the Lithium-Ion Battery ..................................................... 11

FieldFox ON/OFF Settings ............................................................ 12

FieldFox High-Temperature Protection ....................................... 12

Avoid Overpowering the FieldFox ................................................ 13

Take the FieldFox Tour .................................................................. 14

Front Panel....................................................................................... 15

Top Panel ......................................................................................... 16

Right Side Panel.............................................................................. 17

Left Side Panel ................................................................................ 17

Screen Tour ..................................................................................... 18

How to Enter Numeric Values ...................................................... 19

CAT (Cable and Antenna Test) Mode .................................................... 20

CAT Mode Settings ........................................................................ 21

Return Loss Measurements ......................................................... 27

1-Port Cable Loss Measurements ............................................... 28

2-Port Insertion Loss Measurements ......................................... 29

DTF (Distance to Fault) Measurements ................................................ 30

DTF Measurement Settings .......................................................... 31

NA (Network Analyzer) Mode ................................................................ 38

NA Mode Settings .......................................................................... 38

Time Domain - Option 010 ....................................................................... 53

Time Domain (Transform) Settings ............................................. 54

Trace Settings ................................................................................. 58

4 FieldFox User’s Guide

Gating ............................................................................................... 59

Calibration for NA, CAT, and VVM Modes ............................................ 62

Verifying Calibration and Jumper Cable Integrity ..................... 73

Calibration Method Summary ....................................................... 74

SA (Spectrum Analyzer) Mode ............................................................... 75

SA Mode Settings .......................................................................... 76

Channel Measurements .............................................................. 106

Interference Analyzer (SA Mode) Option 236 .................................... 115

Spectrogram and Waterfall Displays......................................... 115

Record Playback ........................................................................... 119

Reflection Mode (SA Models) .............................................................. 128

Reflection Mode Settings............................................................ 129

Channel Power Meter (CPM) Mode Option 310 ................................ 131

CPM Settings ................................................................................ 131

Power Meter Mode ................................................................................ 134

Power Meter Settings .................................................................. 135

VVM (Vector Voltmeter) Mode ............................................................. 140

Overview ........................................................................................ 141

VVM Mode Settings ..................................................................... 141

1-Port Cable Trimming Measurements ..................................... 145

2-Port Transmission Measurements ......................................... 146

A/B and B/A Measurements .................................................... 147

Data Analysis Features .......................................................................... 148

All about Markers ......................................................................... 148

All about Limit Lines .................................................................... 158

All about Trace Math ................................................................... 161

File Management .................................................................................... 164

Saving and Recalling Files .......................................................... 164

Printing ........................................................................................... 171

FieldFox User’s Guide 5

System Settings ...................................................................................... 172

Run/Hold ....................................................................................... 172

Preset ............................................................................................. 173

Audio (Volume) Control ............................................................... 173

Display Settings ............................................................................ 174

Preferences.................................................................................... 176

System Configuration .................................................................. 178

Service Diagnostics ...................................................................... 186

Working with the Lithium-Ion Battery ................................................ 188

Viewing Battery Charge Status .................................................. 188

Charging the Battery .................................................................... 189

Reconditioning the Battery ......................................................... 191

Battery Care ................................................................................... 192

Maximizing Battery Life............................................................... 192

Lithium Ion Battery Disposal ...................................................... 193

Hardkey/Softkey Menus ....................................................................... 194

Safety Considerations ............................................................................ 204

Certification and Compliance Statements ................................ 212

Appendix A: Connector Care Review ................................................... 213

Appendix B: Specifications/Data Sheet ............................................. 214

Appendix C: Instrument Calibration ..................................................... 215

Index ......................................................................................................... 216

6 FieldFox User’s Guide

A.07.00 Firmware Release Updates

For customers upgrading FieldFox firmware, the following is a list of changes from the previous release:

NA Mode

3-trace overlay configuration .............................. 40

External Triggering ............................................... 48

Removed limitations on Marker Table ............. 151

Expanded Marker Formats ................................ 153

Marker Colors ....................................................... 152

SA Mode

InstAlign annotation ........................................... 100

RF Burst Triggering ............................................... 94

RF Burst Alignment............................................. 101

Field Strength Correction (Red) Trace .............. 83

Longer Zero span sweep times ............................ 93

Negative Trigger Delay .......................................... 94

FFT Gating .............................................................. 97

CAT Mode

Distance Units saved to Preferences ................ 176

All Modes (System)

Limit Beep on Pass .............................................. 160

Preferences Quick Settings table ...................... 176

Date and Time change restrictions ................... 184

Power ON .............................................................. 185

NA Factory Cal date ............................................ 186

Overview 7

Model

Max Freq (GHz)

Description

N9913A

Vector Network Analyzer AND Spectrum Analyzer

N9914A

6.5

Vector Network Analyzer AND Spectrum Analyzer

N9915A

Vector Network Analyzer AND Spectrum Analyzer

N9916A

Vector Network Analyzer AND Spectrum Analyzer

N9917A

Vector Network Analyzer AND Spectrum Analyzer

N9918A

26.5

Vector Network Analyzer AND Spectrum Analyzer

N9925A

Vector Network Analyzer

N9926A

Vector Network Analyzer

N9927A

Vector Network Analyzer

N9928A

26.5

Vector Network Analyzer

N9935A

Spectrum Analyzer

N9936A

Spectrum Analyzer

N9937A

Spectrum Analyzer

N9938A

26.5

Spectrum Analyzer

Minimum Frequency: 30 kHz for all models

Accessory Part Number

Description

N9910X–873

AC/DC Adapter

N9910X–870

Lithium-Ion Battery

N9910X–880

Softcase w/ Backpack & Shoulder Strap

N9910X–890

User’s Guide (printed copy)

N9910X–891

Quick Reference Guide (printed copy)

Overview

Models and Options

Models

FieldFox Options: For a comprehensive list, view the FieldFox Configuration Guide at: http://cp.literature.agilent.com/litweb/pdf/5990-9836EN.pdf

Accessories

The following accessories are included with every FieldFox. Spare accessories can be ordered at any time.

To see a complete list of accessories that are available for the FieldFox, please visit: http://www.agilent.com/find/fieldfox.

8 FieldFox User’s Guide

CAUTION

Caution denotes a hazard. It calls attention to a procedure that, if not correctly performed or adhered to, could result in damage to or destruction of the product. Do not proceed beyond a caution notice until the indicated conditions are fully understood and met.

WARNING

Warning denotes a hazard. It calls attention to a procedure which, if not correctly performed or adhered to, could result in injury or loss of life. Do not proceed beyond a warning note until the indicated conditions are fully understood and met.

FieldFox Manuals, Software, and Supplemental Help

The following manuals and software are available for the FieldFox. To see if you have the very latest versions of each of these, please visit our website at:

www.agilent.com/find/fieldfoxsupport.

Check the manual revision on the first page of each manual.

 User’s Guide –This manual, included with shipment.

 Quick Reference Guide – Printed copy with laminated pages for outdoor use

included with shipment.

 Supplemental Online Help - Concepts and Reference information.

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

 FieldFox Data Link Software and Help – Free download.

 Service Guide – Free download.

 Firmware Updates – Check to see if you have the latest FieldFox firmware.

Conventions that are used in the Manual

 Hardkey indicates a front panel button. The functionality of these buttons

does not change.

The six Softkey menus change dynamically and follow these color conventions:

 Softkey Blue indicates an available setting.

 Softkey Green indicates a change in menu level when selected.

 Softkey Black indicates the default or selected setting.

 Softkey Yellow indicates an active entry in process.

 Softkey Grey indicates a key that is NOT available.

Safety Notes

The following safety notes are used throughout this manual. Familiarize yourself with each of the notes and its meaning before operating this instrument. More

pertinent safety notes for using this product are located in “Safety Considerations” on page 204.

Overview 9

Preparing for Initial Use of Your New FieldFox

Check the Shipment

When you receive your FieldFox, check the shipment according to the following procedure:

1. Inspect the shipping container for damage. Signs of damage may include a dented or torn shipping container or cushioning material that indicates signs of unusual stress or compacting. If not damaged, save the packaging material in case the FieldFox needs to be returned.

2. Carefully remove the contents from the shipping container, and verify that the standard accessories and your ordered options are included in the shipment according to the Box Contents List.

3. For any question or problems, refer to Contacting Agilent on page 2.

Meeting Power Requirements for the AC/DC Adapter

Voltage: 100 VAC to 250 VAC

Frequency: 50 Hz to 60 Hz

Current: 1.25 – 0.56 A

The AC/DC adapter supplied with the analyzer is equipped with a three-wire power cord, in accordance with international safety standards. The power cable appropriate to the original product shipping location is included with the FieldFox.

Various AC power cables are available from Agilent that are unique to specific geographic areas. You can order additional AC power cables that are correct for use in different areas. For the power cord part number information please visit:

http://www.agilent.com/find/fieldfox

10 FieldFox User’s Guide

Step

Notes

1. Open the battery door.

Push the button on the battery compartment door while sliding the door outward.

2. Insert the battery.

The terminals end of the battery is inserted into the compartment.

3. Close the battery door.

Slide the battery compartment door upwards until it latches.

Install the Lithium-Ion Battery

Battery Usage

When you receive your FieldFox, the lithium-ion battery is not installed, and it is partially charged to approximately 40% to preserve battery life. A lithium-ion battery has no memory effect, so it can be used partially charged, as shipped.

A fully charged battery will power your FieldFox for about four hours, so if you plan to use it for this long, you should fully charge the battery.

NOTE The FieldFox will shut down to prevent the battery from discharging to a level

that is damaging. If this occurs, charge the battery either internally or externally.

Learn more about the lithium-ion battery on page 188.

Battery charge status is viewable:

 In the upper-right corner of the screen.

 On the Battery screen. To access the screen, select System , Service

Diagnostics, and Battery.

 On the battery. Open the FieldFox battery compartment door to view the

battery LCD.

To conserve battery power:

 Use Run/Hold to single-trigger a measurement when needed. Hold is shown on

the display.

 Press System then Display then Brightness. Use the ▲|▼ arrows, the rotary

knob, or numeric keypad to adjust the brightness to dim the FieldFox display as much as possible.

 Briefly press the power button to switch to Stand By mode when the FieldFox

is not being used. Press again to restore power. All current settings are preserved.

Preparing for Initial Use of Your New FieldFox 11

NOTE When powered by the battery only, the FieldFox can stay in Stand By mode for a

maximum of four hours and then it powers off automatically. When the relative battery charge drops about 20%, the FieldFox will power off to preserve the remaining charge.

To recharge a battery:

Use ONLY a FieldFox charger to recharge a battery.

 The battery can be fully charged while in the FieldFox in about 4 hours with

the FieldFox either ON or OFF.

 The battery can be fully charged externally using the external battery charger

in about 4 hours.

 When the battery is removed, the FieldFox can still be powered by the AC/DC

adapter.

FieldFox ON/OFF Settings

 To turn power ON, briefly press the power button. Boot-up takes about 1

minute.

 To switch to Stand By mode (low battery drain), briefly press the power

button. To turn power ON, briefly press the power button. Power and settings are restored instantly. See the Note above concerning Stand By mode.

 To turn Power OFF (very low battery drain), press and hold the power button

until power is OFF - about 4 seconds. Data and instrument state are NOT automatically saved when the FieldFox is powered OFF. Learn how to save data and instrument state on page 164.

 You can make a setting to automatically Power ON the FieldFox when a power

source is connected. Learn how on page 185.

Power button LED status

 Solid green – Power is ON

 Blinking green – FieldFox in Stand By mode

 Blinking amber – Battery charging.

 Blinking amber and green – Stand By mode and battery charging.

 Not lit – Power is Off and battery is not charging.

FieldFox High-Temperature Protection

The following features prevent degradation or damage in the event of high internal temperatures in the FieldFox.

NOTE Do NOT store the FieldFox in the softcase while powered ON or in Stand By

mode.

How to monitor the internal FieldFox temperature:

 Press System , then Service Diagnostics.

 Then Internal Temperatures.

12 FieldFox User’s Guide

WARNING

Maximum Input Voltages and Power:

RF IN/OUT Connectors: ±50 VDC, +27 dBm RF

DC Input: 19 to 19 VDC, 40 Watts maximum when charging battery

Learn more about Maximum power and voltages in the FieldFox Data Sheet on page 214.

 The temperature at which the following events occur is the average of the RF1,

RF2, SB1, SB2 temperatures. These temperatures come from internal sensors embedded within FieldFox.

Temperature Control Mode

At approximately 73°C, the FieldFox enters Temperature Control mode by reducing display intensity, switching to Outdoor Sun display colors, and reducing measurement speed. This should decrease the internal temperature which preserves measurement accuracy and maintains the long-term reliability of the FieldFox. When this occurs, the following message is displayed on the FieldFox screen:

The system is entering Temperature Control Mode due to high internal temperature.

When entering Temperature Control mode, save your instrument state and data that you want to keep.

When the temperature drops to approximately 71°C, a message is displayed indicating that the FieldFox is leaving Temperature Control Mode and normal operating settings are restored.

NOTE Measurement speed specifications do NOT apply in Temperature Control Mode.

High-Temp Shutdown

In extreme situations, Temperature Control mode may not stop an increase in the FieldFox internal temperature. At approximately 75°C, High-Temperature Shutdown will engage and turn OFF the FieldFox.

Just prior to shutdown, the FieldFox will display a warning of imminent shut down.

Avoid Overpowering the FieldFox

The FieldFox can be damaged with too much power or voltage applied. Exceeding the maximum RF power levels shown below will cause an ADC Over Range message to appear on the screen.

NOTE Very often, coaxial cables and antennas build up a static charge, which, if

allowed to discharge by connecting to the FieldFox, may damage the instrument input circuitry. To avoid such damage, it is recommended to dissipate any static charges by temporarily attaching a short to the cable or antenna prior to attaching to the FieldFox.

Preparing for Initial Use of Your New FieldFox 13

Front Panel

Take the FieldFox Tour

14 FieldFox User’s Guide

No.

Caption

Description

Learn More on Page:

Power

ON: press momentarily.

STAND BY: with FieldFox power ON, press briefly.

OFF: press and hold until the FieldFox shuts off (about 4 seconds).

LED

Not lit: FieldFox OFF, not charging

Green: FieldFox ON. Charging status indicated by battery icon on screen

Orange, flashing: FieldFox STAND BY

Orange, intensity increasing, flashing slowly: FieldFox OFF, charging

System

Displays a submenu for system setup

172

Function keys

Includes: Freq/Dist , Scale/Amptd, BW , Sweep , Trace, Meas

Setup, Measure , and Mode

Refer to specific Mode.

Preset

Returns the analyzer to a known state

173

Enter

Confirms a parameter selection or configuration

Marker

Activates marker function

148

Mkr→/Tools

Displays a submenu for marker functions

153

Esc

Exits and closes the dialog box or clears the character input

Save/Recall

Saves the current trace or recalls saved data from memory

164

Limit

Sets limit lines for quick Pass/Fail judgment

158

Run/Hold

Toggles between free Run and Hold/Single operation.

172

Cal

Displays a submenu for calibration functions

Arrow keys

Increases or decreases a value or setting.

◄Back

Returns to the previous menu selection.

Rotary knob

Highlights an item for selection, or enables incremental changes to values.

Softkeys

Allows selection of settings for configuring and performing measurements, and for other FieldFox functions.

Screen

Transflective screen, viewable under all lighting conditions. If you are using your FieldFox in direct sunlight, you do not need to shield the display from the sunlight. In bright lighting conditions, the display is brighter and easier to read when you allow light to fall directly on the screen. Alternative color modes exist that maximize viewing in direct sunlight conditions, as well as other conditions such as nighttime work.

Note: Clean the Transflective screen with gentle and minimal wiping using Isopropyl alcohol applied to a lint-free cloth.

173 - Display settings

18 - Screen Tour

Front Panel

Preparing for Initial Use of Your New FieldFox 15

Caption

Description

Learn More

Port 1 RF Output

For CAT and NA measurements, use to make reflection measurements. Maximum: ±50 VDC, +27 dBm RF

CAT Mode on page 20

NA Mode on page 38

Port 2 SA RF Input

For SA, use to make all measurements.

For CAT, NA, and VVM mode, use to make Port 2 transmission measurements.

Maximum: ±50 VDC, +27 dBm RF.

SA Mode on page 75

GPS Ant

For use with built-in GPS. Produces a 3.3 VDC bias voltage for the antenna pre-amplifier. Use with a GPS antenna such as N9910X-825. Other GPS antennas can also be used.

GPS on page 179.

Ref In Trig In

Frequency Reference Source and External Trigger Input signal.

Maximum: 5.5 VDC.

Freq. Ref on page 181.

Ext Trig (SA Mode) on page 94

Top Panel

16 FieldFox User’s Guide

Connector

Description

Learn More

Ethernet cable connector to read trace data using the FieldFox Data Link Software.

Download the latest version of the software at:

www.agilent.com/find/fieldfoxsupport

On page 184. IF Out used in SA mode for external signal processing.

On page 91.

Frequency Reference Source Output

Trigger Output – reserved for future development.

On page 181. Secure Digital slot. Use to extend the memory of the FieldFox.

File locations on page 164

Reserved for future use.

Two standard USB connectors used to connect a power sensor for Power Meter Mode. Also used to save files to a USB flash drive.

Use of Keyboard and Mouse is NOT supported.

File locations on page 164

Caption

Description

Learn More

Audio output jack for use with SA Mode Tune and Listen.

On page 86

DC Voltage Source for use with external DC Bias.

On page 182

DC power connector used to connect to the AC/DC adapter. Maximum: 19 VDC, 4 ADC.

On page 11

Right Side Panel

Left Side Panel

Preparing for Initial Use of Your New FieldFox 17

Caption

Description

Learn More on Page:

Title – write your own text here

175 2 Current Mode

3 Run / Hold

172 4 Display Format

Mode dependent

Scale/division

Mode dependent

Calibration Status (CAT and NA)

Detection Method (SA)

Velocity Factor (Fault Meas)

33 8 Averaging Status and Count

Mode dependent

Data / Mem Display (CAT and NA) Step / FFT (SA)

161- Trace Math 86 - Res BW

Resolution Setting

Mode dependent

Measurement Start Freq or Distance

Mode dependent

Bandpass / Lowpass setting (Fault Meas) IF BW in NA Mode

Output Power Level (CAT and NA)

Measurement Stop Freq or Distance

Mode dependent

Actual Sweep Time

Mode dependent

Limit Line Status

158

Time and Date

179

Marker Readout

148

Battery Status

188

Measurement Type (CAT and NA)

Reference Level

Mode dependent

Reference Position

Mode dependent

Screen Tour

18 FieldFox User’s Guide

How to Enter Numeric Values

Many settings on the FieldFox require the entry of numeric values.

How to enter numeric values

Use any combination of the following keys:

 Numeric 0–9 keys, along with the polarity ( +/- ) key.

 Up/Down arrow keys to increment or decrement values.

 Rotary knob to scroll through a set of values.

 Back erases previously entered values.

 Esc exits data entry without accepting the new value.

To complete the setting:

 Press Enter or a different softkey or hardkey.

Multiplier Abbreviations

Many times after entering numeric values, a set of multiplier or suffix softkeys are presented. The following explains the meaning of these abbreviations.

Select Frequency multipliers as follows:

 GHz Gigahertz (1e9 Hertz)

 MHz Megahertz (1e6 Hertz)

 kHz Kilohertz (1e3 Hertz)

 Hz Hertz

Select Time multipliers as follows:

 s Seconds

 ms milliseconds (1e–3)

 us microseconds (1e–6)

 ns nanoseconds (1e–9)

 ps picoseconds (1e-12)

Preparing for Initial Use of Your New FieldFox 19

CAT (Cable and Antenna Test) Mode

CAT Mode is typically used to test an entire transmission system, from the transmitter to the antenna. This process is sometimes referred to as Line Sweeping.

CAT Mode is similar to NA (Network Analyzer) Mode. Learn more in the

Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

CAT Mode Distance to Fault measurements are discussed on page 30.

In this Chapter

Measurement Selection ......................................... 21

Coupled Frequency ............................................... 22

Quick Settings ........................................................ 22

Frequency Range ................................................... 23

Scale Settings ......................................................... 23

Averaging ............................................................... 24

Single/Continuous ................................................. 25

Resolution ............................................................... 25

Sweep Time ............................................................. 25

Output Power ......................................................... 26

Interference Rejection .......................................... 26

Procedures

Return Loss Measurement ................................... 27

1-Port Cable Loss Measurement .......................... 28

2-Port Insertion Loss Measurement ................... 29

Distance to Fault Measurements ......................... 30

See Also

All about Calibration ............................................. 53

Set Markers ........................................................... 148

Use Limit Lines .................................................... 158

Use Trace Math .................................................... 161

Making 75Ω (ohm) Measurements at the FieldFox Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

20 FieldFox User’s Guide

CAT Mode Settings

Select CAT Mode before making any setting in this chapter.

How to select CAT Mode

 Press Mode .

 Then CAT.

Measurement Selection

How to select a CAT Mode Measurement

Learn more about the following measurements in the Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

 Press Measure 1 .

 Then choose one of the following: These softkeys also appear after CAT Mode

is selected.

o Distance to Fault 1-port reflection measurement that uses Inverse Fourier

Transform (IFT) calculations to determine and display the distance to, and relative size of, a fault or disruption in the transmission line. Units are in return loss format, expressed as a positive number in dB, unless the measurement selected is DTF (VSWR). Learn more about DTF Measurements on page 30.

o Return Loss & DTF Displays both a Return Loss measurement and a DTF

measurement. Use this format to display the frequency settings that are used to make the DTF measurement. The frequency range settings for these two measurements can be coupled or uncoupled. Learn more on page 22.

o Calibrations are applied to both traces.

o When in Hold mode and Single sweep is performed, only the active trace

is triggered. Use the ▲|▼ arrows to activate a trace.

o Return Loss 1-port reflection measurement that displays the amount of

incident signal energy MINUS the amount of energy that is reflected. The higher the trace is on the screen, the more energy being reflected back to the FieldFox. Learn how to measure Return Loss on page 26.

o VSWR (Voltage Standing Wave Ratio – also known as SWR) 1-port reflection

measurement that displays the ratio of the maximum reflected voltage over the minimum reflected voltage. The higher the trace is on the screen, the more energy being reflected back to the FieldFox.

o DTF (VSWR) Distance to Fault in VSWR format.

o Cable Loss (1-Port) 1-port reflection measurement that displays the loss of

a transmission line. Learn more on page 26.

CAT (Cable and Antenna Test) Mode 21

o Insertion Loss (2-Port) 2-port transmission measurement that accurately

displays the loss through a cable or other device in dB. Both ends of the cable must be connected to the FieldFox. NO phase information is included in this measurement. Learn more on page 29. This feature is available only with an option on some FieldFox models. For detailed information, please view the FieldFox Configuration Guide at:

http://cp.literature.agilent.com/litweb/pdf/5990-9836EN.pdf

o DTF (Lin) Distance to Fault in Linear format.

Coupled Frequency

This setting is available ONLY when a Return Loss & DTF measurement is present and the DTF measurement is active. Otherwise, Coupled Frequency is set to ON and can NOT be changed.

Coupled Frequency ON (default setting) – Both traces have the same frequency range settings.

Coupled Frequency OFF - Both traces are allowed to have individual frequency range settings. When set to OFF:

 The Return Loss measurement frequency settings are made in the usual

manner. Learn how on page 23. When a new Start or Stop frequency is selected, Coupled Frequency is automatically set to OFF.

 The DTF measurement is made using the frequencies as determined by the

DTF Frequency Mode setting. Learn more on page 32.

How to set Coupled Frequency

With a Return Loss & DTF measurement present:

 Press Meas Setup 4

 Select the DTF measurement (Tr2) using the ▲|▼ arrows.

 Then Coupled Freq ON OFF

Quick Settings Table

Both CAT and NA Modes allow you to view and change most relevant settings from a single location. All of these settings are discussed in this chapter and, unless otherwise noted, ALL of these settings can also be made using the standard softkey menus.

How to view and change Quick Settings

 Press Meas Setup 4 .

 Then Settings.

 Press Next Page and Previous Page to view all settings. If these softkeys are

NOT available, then all available settings fit on one page.

 To change a setting:

o Use the ▲|▼ arrows to highlight a setting.

o Then press Edit. The current setting changes to yellow.

22 FieldFox User’s Guide

o Some settings require you to press a softkey to change the value. Otherwise,

use the numeric keypad, ▲|▼ arrows, or rotary knob to change the value.

o When finished changing a value, press Done Edit.

 Press Dock Window to relocate the Settings table to a position relative to the

trace window. The Dock Window setting persists through a Preset. Choose from the following:

o Full (Default setting) Only the Settings table is shown on the screen. The

trace window is temporarily not shown.

o Left The Settings table is shown to the left of the trace window.

o Bottom The Settings table is shown below the trace window.

 When finished changing ALL settings, press Done to save your settings.

Frequency Range

Set the range of frequencies over which you would like to make CAT Mode measurements.

When the frequency range is changed after a calibration is performed, the cal becomes interpolated. Learn more on page 71.

How to set Frequency Range

 Press Freq/Dist .

 Then choose from the following:

o Start and Stop frequencies - beginning and end of the sweep.

o Center and Span frequencies – the center frequency and span of

frequencies (half on either side of center).

 Follow each setting by entering a value using the numeric keypad, ▲|▼

arrows, or the rotary knob.

o After using the keypad, select a multiplier key. Learn about multiplier

abbreviations on page 19.

o After using the ▲|▼ arrows or the rotary knob, press Enter . The amount of

frequency increment is based on the current span and can NOT be changed in CAT Mode.

Scale Settings

Adjust the Y-axis scale to see the relevant portions of the data trace. The Y-axis is divided into 10 graticules.

This setting can be changed at any time without affecting calibration accuracy.

How to set Scale

 Press Scale / Amptd .

 Then choose from the following three methods:

1. Autoscale Automatically adjusts the Y-axis to comfortably fit the Min and Max amplitude of the trace on the screen.

2. Set Scale, Reference Level, and Reference Position:

CAT (Cable and Antenna Test) Mode 23

Scale annotation on the FieldFox screen

· Reference Line = red arrow

·Ref Level = -40 dB

· Ref Position = 1

· Scale = 2 dB per division

o Scale Manually enter a scale per division to view specific areas of the trace.

o Ref Level Manually set the value of the reference line. Enter a negative

value by pressing Run/Hold (+/-) either before or after typing a value.

o Ref Position Manually set the position of the reference line. Values must be

between 0 (TOP line) and 10 (BOTTOM line)

3. Set Top and Bottom graticule values. The scale per division is calculated.

o Top to set the value of the Top graticule.

o Bottom to set the value of the Bottom graticule.

o Enter a negative value by pressing Run/Hold (+/-) either before or after

typing a value.

Averaging

Trace Averaging helps to smooth a trace to reduce the effects of random noise on a measurement. The FieldFox computes each data point based on the average of the same data point over several consecutive sweeps.

Average Count determines the number of sweeps to average; the higher the average count, the greater the amount of noise reduction.

An average counter is shown in the left edge of the screen as Avg N. This shows the number of previous sweeps that have been averaged together to form the

current trace. When the counter reaches the specified count, then a ‘running average’ of the last N sweeps is displayed. Average Count = 1 means there is NO

averaging.

This setting can be changed at any time without affecting calibration accuracy.

NOTE Averaging is often used to increase the dynamic range of a measurement. To

achieve the highest dynamic range, select NA mode and reduce the IF Bandwidth setting. Learn more about dynamic range on page 51.

How to set Trace Averaging

 Press BW 2 .

 Then Average N where N is the current count setting.

 Enter a value using the numeric keypad. Enter 1 for NO averaging.

 Press Enter .

 While Trace Averaging is in process, press Sweep 3 then Restart to restart

24 FieldFox User’s Guide

the averaging at 1.

Single or Continuous Measure

This setting determines whether the FieldFox sweeps continuously or only once each time the Single button is pressed. Use Single to conserve battery power or to allow you to save or analyze a specific measurement trace.

This setting can be changed at any time without affecting calibration accuracy.

How to set Single or Continuous

 Press Sweep 3 .

 Then choose one of the following:

o Single Automatically sets Continuous OFF and causes FieldFox to make

ONE sweep, then hold for the next Single key press. Hold is annotated in the upper left corner of the display when NOT sweeping, and changes to an arrow --> while the sweep occurs.

o Continuous Makes continuous sweeps. This is the typical setting when

battery power is not critical.

You can also use Run / Hold +/- to toggle between Single and Continuous.

Resolution (Number of Data Points)

Data points are individual measurements that are made and plotted across the Xaxis to form a trace. Select more data points to increase measurement resolution. However, more data points require more time to complete an entire measurement sweep.

When the Resolution is changed after a calibration is performed, the cal becomes interpolated. Learn more on page 71.

How to set Resolution

 Press Sweep 3 .

 Then Resolution .

 Then choose one of the following:

101 | 201 | 401 | 601 | 801 | 1001 |1601 | 4001 | 10001.

 Using SCPI, Resolution can be set to any number of points between 3 and

10001. See the Programming Guide at http://na.tm.agilent.com/fieldfox/help/

Sweep Time

The fastest possible sweep time is always used as the default setting. Use the Min Swp Time setting to slow the sweep time when measuring long lengths of cable.

Learn more in the Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm.

The actual sweep time is shown on the FieldFox screen. See the Screen Tour on page 18. To increase the sweep time, enter a value that is higher than the actual sweep time. The increase will not be exactly the amount that you enter, as the actual sweep time is the composite of many factors.

NOTE Measurement speed specifications do NOT apply in Temperature Control Mode.

Learn more on page 13.

CAT (Cable and Antenna Test) Mode 25

How to set Sweep Time

 Press Sweep 3 .

 Then Min Swp Time.

 Enter a value using the numeric keypad.

 Press a multiplier key. Learn about multiplier abbreviations on page 19.

Output Power

Set the power level out of the FieldFox to High, Low, or manually set power level to a value between High and Low.

Generally, the high power setting is used when measuring passive, high-loss devices to place the signal farther from the noise floor. However, for devices that are sensitive to high power levels such as amplifiers, use the Low power setting.

For best measurement accuracy, use the Manual power setting at -15 dBm. After calibration, the power level can be decreased for amplifiers, or increased for higher dynamic range.

Caution Power Level settings in this mode will NOT change Power Level settings in other

modes. To help prevent damage to your DUT, use caution when changing modes with your DUT connected to the FieldFox test ports.

How to set Output Power

 Press Meas Setup 4 .

 Then Power

 Then Output Power

o High (Default setting) Sets output power to the maximum achievable power

at all displayed frequencies. Output power is NOT FLAT across the displayed FieldFox frequency span. Please see the FieldFox Specifications (page 214) for expected power levels.

o Low Sets output power to approximately –45 dBm, FLAT across the

displayed FieldFox frequency span.

o Man Set output power to an arbitrary value, FLAT across the displayed

FieldFox frequency span. If flattened power can NOT be achieved, a warning message and beep occurs. To achieve a flattened output power, reduce the power level or stop frequency.

o Then press Power Level

o Then enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary

knob.

o Press Enter.

26 FieldFox User’s Guide

Interference Rejection

Use this setting when you suspect that other signals in the area are interfering with a measurement. Interference may look like a spike or lack of stability in the measurement trace. While monitoring a measurement at a specific frequency, toggle this setting between ON and OFF. If the measurement result decreases while ON, then there is an interfering signal in the area. Continue to make measurements with Interference Rejection ON. However, this will slow the measurement speed.

Once enabled, up to SIX sweeps may be required before the interfering signal is neutralized.

This setting can be changed at any time without affecting calibration accuracy.

How to set Interference Rejection

 Press Meas Setup 4 .

 Then Interference Rejection [current setting].

 Then choose from the following:

o Off No interference rejection and fastest possible sweep speed.

o Minimum The lowest level of Interference rejection.

o Medium The medium level of Interference rejection.

o Maximum The highest level of Interference rejection.

Return Loss Measurements

Return loss can be thought of as the absolute value of the reflected power as compared to the incident power.

When measuring an OPEN or SHORT, all incident power is reflected and approximately 0 dB return loss is displayed.

When measuring a LOAD, very little power is reflected and values of 40 dB to 60 dB are displayed.

The minus sign is usually ignored when conveying return loss. For example, a component is said to have 18 dB return loss, rather than –18 dB.

How to measure Return Loss

 Connect the cable or any adapter used to connect the device under test (DUT).

 Select Preset then Preset Returns the FieldFox to known settings.

 Select Mode then CAT (Cable and Antenna Test)

 Then Return Loss (Default measurement).

 Press Freq/Dist and enter Start and Stop frequency values of the

measurement.

 Press Meas Setup 4 then Settings to make appropriate settings before

calibrating.

 Disconnect the cable or DUT and press Cal 5 then follow the calibration

prompts.

 Reconnect the cable or DUT.

CAT (Cable and Antenna Test) Mode 27

 The return loss trace is displayed on the FieldFox screen.

1-Port Cable Loss Measurements

While all cables have inherent loss, weather and time will deteriorate cables and cause even more energy to be absorbed by the cable. This makes less power available to be transmitted.

A deteriorated cable is not usually apparent in a Distance to Fault measurement, where more obvious and dramatic problems are identified. A Cable Loss measurement is necessary to measure the accumulated losses throughout the length of the cable.

A 2-port Insertion Loss measurement is usually more accurate than a 1-port Cable Loss measurement. However, to perform a 2-port Insertion Loss measurement, both ends of the cable must be connected to the FieldFox.

NOTE In high-loss conditions, a Cable Loss measurement becomes ‘noisy’ as the test

signal becomes indistinguishable in the FieldFox noise floor. This can occur when measuring a very long cable and using relatively high measurement frequencies. To help with this condition, use High Power (page 26) and Averaging. (page 24).

How to make a 1-port Cable Loss Measurement

1. Press Preset then Preset.

2. Then More then Cable Loss (1-Port) .

3. Connect the cable to be tested.

4. Press Freq/Dist and enter Start and Stop frequency values of the measurement.

5. Press Sweep 3 then Min Swp Time. Increase the Sweep Time until a stable trace is visible on the screen. The amount of time that is required increases with longer cable lengths. Learn more in the Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

6. Remove the cable to be tested.

7. Press Cal 5 , then QuickCal or Mechanical Cal.

8. Follow the prompts to perform calibration at the end of the jumper cable or adapter. Learn more about Calibration on page 64.

9. Connect the cable to be tested.

NOTE Low-level standing waves (also known as ‘ripple’) which may be visible in

reflection measurements, can hide the actual loss of the cable. Steps 10 through 13 can minimize the ripple. Perform the measurement with and without steps 10 through 13 and choose the method with the least amount of ripple.

10. Connect a LOAD at the end of the cable to be tested. This limits the reflections to faults that are located in the cable under test.

11. Press Trace 6 then Data->Mem to store the trace into Memory.

12. Remove the LOAD and leave the end of the cable to be tested open.

13. Press Data Math then Data – Mem. The ripple in the measurement is removed. These minor imperfections in the cable should not be considered in the Cable Loss measurement.

14. Use Averaging to remove random noise from high-loss measurements. Press

BW 2 then Average.

28 FieldFox User’s Guide

The displayed trace shows the Cable Loss values in one direction through the cable. A Return Loss measurement would show the loss for both down the cable and back. Therefore, a Cable Loss measurement is the same as a Return Loss measurement divided by 2.

The average Cable Loss across the specified frequency range is shown on the screen below the graticules.

2-Port Insertion Loss Measurements

A 2-port Insertion Loss measurement is used to measure the loss through a DUT (device under test) – or cable – over a specified frequency range. The FieldFox signal source is transmitted out the RF OUT connector, through the DUT, and into the RF IN connector. Both ends of the DUT must be connected to the FieldFox, either directly or indirectly using the cable used in the normalization cal.

‘Insertion’ loss simply means loss through a device, usually expressed in dB. It is exactly the same measurement as “S21 Transmission” in NA Mode.

2-port Insertion Loss measurements are generally more accurate than 1-port Cable Loss measurements.

How to make a 2-port Insertion Loss Measurement

1. Press Mode then CAT.

2. Then More then Insertion Loss (2-Port) .

3. Press Freq/Dist and enter Start and Stop frequency values of the measurement.

4. Press Sweep 3 , then select a Resolution setting.

5. Press Cal 5 , then perform a calibration. Learn more on page 68.

6. Connect the DUT and view the insertion loss measurement results.

When measuring very long lengths of cable, it may be necessary to increase the sweep time. Learn how on page 25. Learn why in the Supplemental Online

Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

CAT (Cable and Antenna Test) Mode 29

DTF (Distance to Fault) Measurements

CAT Mode Distance to Fault (DTF) measurements are generally used to locate problems, or faults, in a length of cable or transmission line. In this chapter, the cable to be tested is referred to as the DUT (Device Under Test).

Settings that are NOT unique to DTF measurements are documented in the CAT Mode chapter on page 20.

In this Chapter

How to make DTF Measurements ....................... 30

DTF Settings Table ................................................ 31

DTF Measurement (Format) ................................ 31

DTF Start and Stop Distance ............................... 31

Frequency Mode ..................................................... 32

Coupled Frequency ............................................... 33

Cable (Correction) Specifications ....................... 33

Window Settings .................................................... 36

DTF Units ................................................................ 36

Calculated DTF Values .......................................... 36

About Alias Faults ................................................. 37

Optional settings

Markers .................................................................. 148

Limit Lines ............................................................ 158

Save Measurement Settings and Results ......... 164

Trace Math is NOT available in DTF Measurements.

How to make DTF Measurements

Before starting, you may need the following:

 Jumper cable or adapter to connect the beginning of the DUT to the FieldFox.

 LOAD with correct connector type and gender to terminate the end of the DUT

(if possible).

 The known length and cable type of the DUT. If the cable type is not known,

then the Cable Loss (dB/Meter) and Velocity Factor of the DUT are required.

1. Connect any necessary jumper cable or adapter to the FieldFox RF OUT port. Do NOT connect the DUT.

2. Press Preset then Preset to return the FieldFox to the default settings.

3. Then Mode then CAT.

4. Then DTF .

5. Press Freq/Dist , then Stop Distance and enter the length of the DUT. You can optionally set the Start Distance.

6. Press Cal 5 and follow the Cal prompts. Learn all about Calibration on page 53.

30 FieldFox User’s Guide

7. Disconnect any components or antenna that should NOT be measured and connect a LOAD at the end of the DUT.

8. Press Meas Setup 4 then DTF Cable Specifications.

9. Either press Recall Coax Cable, or enter the Velocity Factor and Cable

Loss of the DUT.

10. Connect the start end of the DUT to the FieldFox.

11. Press Meas Setup 4 then Settings then Next Page. If the Alias-free Range setting is False, then you may see Alias faults on the screen. Learn more on page 37.

DTF Measurement Settings

DTF Settings Table

You can set and view all of the DTF settings, including some calculated values, on the DTF Settings table. Learn about the calculated values on page 36.

How to make settings on the DTF settings table

 Press Meas Setup 4 .

 Then Settings.

 Press Next Page and Previous Page to view all settings.

 To change a setting:

o Use the ▲|▼ arrows or rotary knob to highlight a setting.

o Numeric settings can be changed by pressing numbers using the numeric

keypad. Then press Enter or select a suffix if available.

o Other settings require you to press Edit, then press a softkey to change the

value.

o When finished changing a value, press Done Edit.

 Press Dock Window to relocate the Settings table to a position relative to the

trace window. The Dock Window setting persists through a Preset. Choose from the following:

o Full (Default setting) Only the Settings table is shown on the screen. The

trace window is temporarily not shown.

o Left The Settings table is shown to the left of the trace window.

o Bottom The Settings table is shown below the trace window.

 When finished changing ALL settings, press Done to save your settings.

DTF Measurement (Format)

You can select from 3 different DTF Formats.

 Press Measure 1

 Then choose from:

o Distance to Fault (dB) Faults are displayed on the Y-axis in return loss

format, expressed as a positive number in dB.

DTF (Distance to Fault) Measurements 31

o DTF (VSWR) Faults are displayed on the Y-axis in SWR. Learn more about

SWR at the FieldFox Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

o More then DTF Lin Faults are displayed on the Y-axis in linear (unitless)

format.

DTF Start and Stop Distance

In DTF measurements, you set the physical length of cable or other device to be tested. The FieldFox calculates the frequency range of the measurement from this distance. The longer the cable to be tested, the lower the frequencies that are used. You can also set the frequencies manually using the Frequency Mode [Bandpass] setting.

How to set Start and Stop Distance

 With a DTF measurement present, press Freq/Dist .

 Then choose from the following:

o Start Distance Enter a value using the numeric keypad, the ▲|▼ arrows,

or the rotary knob, then Enter. By default, the Start Distance is set to 0 Meters. This means that the measurement will display faults starting at the point at which calibration standards are connected.

o Stop Distance Enter a value between the start distance and 5 km (or

16,404 ft.) using the numeric keypad, the ▲|▼ arrows, or the rotary knob, then Enter .

Frequency Mode

All DTF measurements are made with frequency settings and, using Inverse Fourier Transform (IFT), the time and distance to faults are calculated.

How to set Frequency Mode

With a DTF measurement present,

 Press Meas Setup 4

 Then Frequency Mode

 Choose one of the following:

o Lowpass Mode The frequency range of a DTF measurement is set

automatically based on the Start and Stop Distances. Use Lowpass mode when the DUT is a cable ONLY.

o Bandpass Mode (Default setting) The frequency range of a DTF

measurement is set manually. Use Bandpass mode when the DUT contains a diplexer or other filtering device which does not pass some frequencies.

Typically, you will set the frequency range of the measurement to the passband of the filter. However, you may also want to test the ability of the filter to reject unwanted frequencies. In this case, set the frequency range to include those frequencies which the filter may not be adequately rejecting.

32 FieldFox User’s Guide

When the DTF frequencies are set manually, they may not be the optimum frequencies for measuring the distance to fault. The distance may no longer be alias-free. Learn more about alias-free range on page 37.

How to manually set Frequencies in Bandpass Mode

 Press Freq/Dist

 Then Min Start Freq and type the start frequency to use for the DTF

measurement.

 Then Max Stop Freq and type the stop frequency to use for the DTF

measurement.

 OR

 Press More

 Then Max Freq Span and type the frequency range to use for the DTF

measurement.

 Then Center Frequency and type the center frequency of the range to use for

the DTF measurement.

These settings specify the minimum and maximum frequencies to be used for the DTF measurement. These exact frequencies may not be used, but a narrower frequency range may be used that will still pass through the bandpass filter.

To see the frequencies that are used in the DTF measurement, press Meas Setup

4 then Settings then Next Page. The calculated Start and Stop frequencies

determine the exact frequency range being used.

Coupled Frequency

When a Return Loss & DTF measurement is present, this setting allows you to have different frequency ranges for each measurement. Learn more on page 22.

Cable (Correction) Specifications

By default, the FieldFox does NOT correct DTF measurements to account for the inherent loss of a cable. However, to make more accurate DTF measurements, the Cable Loss and Velocity Factor values should be considered.

About Velocity Factor and Cable Loss

o Velocity Factor is a property of the physical material of a cable. A VF of 1.0

corresponds to the speed of light in a vacuum, or the fastest VF possible. A polyethylene dielectric cable has VF = 0.66 and a cable with PTFE dielectric has VF = 0.7.

o Cable Loss is specified in dB/meter. In addition to the length of the cable,

loss is also directly proportional to the frequency of the signal that passes through the cable.

The following is an example showing how DTF cable correction works:

The DUT is a 100 meter transmission cable. The Cable Loss value is .1 dB/meter. This means that a signal traveling ONE WAY through the cable will lose 10 dB of power (100 m * .1dB/m). Because the FieldFox performs this measurement with 1 port, the test signal travels down the cable and then back, for a total loss of 20 dB.

DTF (Distance to Fault) Measurements 33

After a calibration has been performed, for the purpose of illustrating this point, connect an OPEN to the end of the cable – a maximum-sized fault - for 100% reflection of the 300 MHz test signal.

Without compensation for the loss of the cable, a –20 dB response would be visible at 100 meters, which is the OPEN at the end of the DUT. This is from 10 dB of loss through the cable in each direction.

With compensation for the loss using the manufacturer’s specification, the FieldFox compensates the trace as though the signal traveling through 100 meters was increased by +20 dB. Therefore the response will show 0 dB for 100% reflection.

How to enter Cable Loss and Velocity Factor

Cable Loss and Velocity factor can be entered using one of the following methods:

 Manually enter cable loss and velocity factor for the measurement.

 Select or create a cable file which contains the cable loss and velocity factor.

With a DTF measurement present:

 Press Meas Setup 4 .

 Then DTF Cable Specifications

 Select Cable Corr

o Auto Use Cable Loss and Velocity Factor values from a Cable file. See “How

to Edit, Save, and Recall a Cable File” below. This will overwrite a manually-

entered value.

o Man (Default setting) Manually enter a value for Cable Loss and Velocity

Factor.

 Then:

o Velocity Factor Using the numeric keypad, enter a value between 0.01 and

1. Then press Enter .

o Cable Loss Using the numeric keypad, enter a positive Cable Loss value in

dB/m, then press Enter .

How to Edit a Cable File

The FieldFox includes many predefined cable files with the manufacturer’s

specifications. You can edit these files or create new cable files using the following procedure or using the FieldFox Data Link Software. Learn more at:

The Cable correction data survives a Mode Preset and Preset.

With a DTF measurement present:

 Press Meas Setup 4

 Then DTF Cable Specifications

 Then Edit/Save/Recall Cables

 Press New then Yes to clear all data from the existing DTF Cable table and

reset header information to default settings.

 Then Edit Cable to open the Cable Editor.

34 FieldFox User’s Guide

 Then use the ▲|▼ arrows to select a field,

o When editing Cable Description information, press Edit then modify the

selected field using the FieldFox labeler.

o When editing Frequency/Loss pairs, enter numbers using the numeric

keypad, then select a frequency suffix. Then Enter. Learn more about “How the Freq/Loss pairs are applied” below.

 Optionally choose from the following:

o Previous / Next Page Quickly scrolls through pages of Freq/Loss data.

o Add Data Add a blank Freq/Loss pair to the table,

o Delete/Clear then:

o Delete Line Remove the selected Freq/Loss pair from the table.

o Clear All then Yes Remove all Freq/Loss pairs from the table and resets

header information to default settings.

 Press Done to close the Cable Editor.

How to Save or Recall a Cable

 Press Save Cable to saves your changes to the specified Storage Device. Enter

a filename using the FieldFox labeler (learn more on page 164). Learn more about Cable files below.

 Press Recall Cable to load a Cable file from the specified Storage Device.

 Storage Device Changes the device used to save or recall Cable files. This is a

different setting from the Save/Recall Storage Device setting. Choose from

Internal (default setting), USB (must be connected) or SD card.

About Cable files

 Cable files are saved to, and recalled from, the Cables folder. If the folder does

not already exist on a USB or SD card, it is created automatically before storing the file.

 Cable files are stored as *.xml files. Existing cable files that are preloaded into

the FieldFox firmware can be overwritten. Your edited file will NOT be overwritten when firmware is updated.

How the Freq/Loss pairs are applied

When the cable file contains one Freq/Loss pair, that correction value is applied to the entire displayed frequency span.

When the cable file contains two or more Freq/Loss pairs, the Loss value that is used is interpolated from the Freq/Loss pairs and the DTF center frequency. For example, using a cable file with the following Freq/Loss pairs:

1 GHz: 0.1 dB/m

2 GHz: 0.2 dB/m

The center frequency for the measurement is determined from the calculated (Stop – Start) frequency values (seen on the second page of DTF Settings):

Calculated Start = 2.0 MHz

Calculated Stop = 3.598 GHz

DTF (Distance to Fault) Measurements 35

Center Freq = 1.80 GHz

The Loss value for the measurement is interpolated from the Freq/Loss pairs at the Center Freq:

1 GHz = 0.1 dB/m

1.8 GHz = 0.18 dB/m

2 GHz = 0.2 dB/m

The correction for loss at 5 meters in one direction: 0.18 dB/m * 5m = 0.9 dB.

All DTF measurements correct for loss for travel down the DUT and back, so double the correction: 0.9 dB * 2 = 1.8 dB.

Window Settings

Window settings provide the ability to choose between optimizing DTF measurements for resolving closely-spaced faults or for the ability to measure low-level faults.

How to select Window settings

 Press Meas Setup 4 .

 Then Settings.

 Then press ▲|▼ arrows to move to the Window row.

 Then press Edit.

 Then press Window repeatedly and choose from the following:

o Maximum – Optimized for dynamic range, the noise floor is lowered to

provide the ability to measure low-level responses. (Default setting)

o Medium – Compromise between Min and Max window settings.

o Minimum – Best Response Resolution, providing the ability to resolve

between two closely-spaced responses.

 Then press Done Edit.

 Again press Done .

DTF Units

The DTF Units setting is available ONLY on the DTF Settings table.

By default, X-axis units for DTF measurement settings are displayed in Meters.

How to change DTF units

 With a DTF measurement present, press Freq/Dist .

 Then DTF Units.

 The current selection is underlined m (meters) Feet.

Calculated DTF values

Press Next Page on the DTF Settings Table to view the following calculated Values noted on the FieldFox screen with c - <setting>

Start Frequency – Start frequency that is used to calculate DTF.

36 FieldFox User’s Guide

Stop Frequency – Stop frequency that is used to calculate DTF.

Range Resolution. Indicates the accuracy of the distance to fault measurement.

For example, with range resolution of 500 mm, if the distance to fault is 10 meters, this value could be inaccurate by +/- 500 mm or between 9.5 to 10.5 meters. This value is calculated from frequency span / resolution (points).

Response Resolution, not displayed, indicates the distance that could be between two faults and still show as separate faults. Learn more in Window Settings on page 36.

Maximum Distance. The distance that could be viewed with the current settings. Defined by: Vf*c*Points/(2*Bandwidth) where:

o Vf = velocity factor

o c = speed of light

o Points = resolution

o Bandwidth = frequency range

Alias-free Range (On/Off)

o On = No Alias images

o Off = Alias images may appear in the response.

About Alias Faults

An alias fault is not a true device response. An alias fault appears because of the method used to convert frequency to time.

On the DTF Settings page (above) the c - Alias-free Range = Off setting indicates alias images MAY appear on the screen.

Shorter stop distances (less than 10 meters) and a higher resolution (1001 points) will be more likely to result in Alias-free Range = Off.

When the Alias-free Range = Off, the following procedure will help to determine if a response is true or an alias response:

1. Put a marker on the response in question and note the distance to the fault.

2. Change the start or stop distance.

A true fault response will not move in distance. That is, if a true fault is present at 10.3 meters, changing the stop distance from 15 m to 20 m will not move the fault; the fault will remain at 10.3 meters. However, an alias response will appear to move.

An un-terminated cable (with NO perfect load at the end) will show faults that appear to be beyond the end of the cable. These are NOT alias faults. These faults appear as the signal reflects off the open at the end of the cable and travels back down the cable toward the connection at the FieldFox. Re-reflections are measured at the FieldFox as mirror images of the original faults. The largest fault is the open end of the cable. To avoid confusion, set the Stop distance shortly after that fault.

DTF (Distance to Fault) Measurements 37

NA (Network Analyzer) Mode

Learn more about NA Mode measurements in the FieldFox Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

In this Chapter

How to Measure S-parameters ............................ 39

Receiver Measurements ........................................ 40

Multi-Trace Configurations .................................. 40

Quick Settings ........................................................ 42

Format ..................................................................... 42

Frequency Range ................................................... 43

Scale Settings ......................................................... 44

Electrical Delay ...................................................... 44

Phase Offset ............................................................ 45

Averaging ................................................................ 45

IF Bandwidth .......................................................... 46

Smoothing ............................................................... 46

Single/Continuous ................................................. 46

Resolution (number of points) ............................ 47

Sweep Time ............................................................. 48

Output Power ......................................................... 48

System Impedance ................................................. 49

Port Extensions ...................................................... 50

Velocity Factor ....................................................... 51

Increase Dynamic Range ...................................... 51

See Also

All about Calibration ............................................. 53

Set Markers ........................................................... 148

Use Limit Lines .................................................... 158

Use Trace Math .................................................... 161

Learn how to make 75Ω (ohm) Measurements in the Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

NA Mode Settings

Select NA Mode before making any setting in this section.

How to select NA Mode

 Press Mode_ .

 Then NA.

38 FieldFox User’s Guide

About S-parameters

S-parameters (scattering parameters) are used to describe the way a device modifies a signal. The FieldFox can measure four S-parameters. The syntax for each parameter is described by the following:

S (out | in)

out = FieldFox receiver port

in = FieldFox source port

The FieldFox automatically switches the internal source and receivers to make both forward and reverse measurements. Therefore, the FieldFox can measure all four S-parameters with a single connection.

When the source comes from port 1, the measurement is said to be in the forward direction.

When the source comes from port 2, the measurement is said to be in the reverse direction.

S11 and S22 reflection measurements are used to measure the amount of reflections off the corresponding DUT port. Low reflections means there is a good impedance match between the source and DUT.

S21 and S12 transmission measurements are used to measure the loss or gain through a DUT over a specified frequency range. Both ends of the DUT must be connected to the FieldFox. The FieldFox signal source is transmitted out one of the test port connectors, through the DUT, and into the other test port connector.

How to measure S-parameters

1. Press Preset then Preset

2. Press Measure 1 then choose from the following:

o S11 Reflection measurement at port 1.

o S21 Forward 2-port transmission measurement.

o S12 Reverse 2-port transmission measurement. May require an option.

o S22 Reflection measurement at port 2. May require an option.

OR select a multi-trace configuration. Learn more on page 40.

3. Press Freq/Dist then either Start and Stop or Center and Span to enter a Frequency Range for the measurement.

4. Press BW 2 then IFBW to select the IF Bandwidth for the measurement. Narrower bandwidths require more time to sweep, but lowers trace noise.

NA (Network Analyzer) Mode 39

A Port-1 test port (*1)

B Port-2 test port (*2)

R1 Port-1 reference receiver (*1)

R2 Port-2 reference receiver (*2)

5. Press Sweep 3 then Resolution to select the number of data points for the measurement. More data points require more time to sweep.

6. Press Cal 5 to calibrate the measurement. Learn more on page 62.

7. All other settings can be made AFTER calibration without compromising measurement accuracy.

Receiver Measurements

In NA Mode ONLY, you can make unratioed, uncorrected receiver measurements. These measurements are typically used as diagnostic tools for service personnel.

NOTE The receivers measurements are NOT corrected for absolute power. They are

only useful for making relative measurements. The Y-Axis and markers are labeled in dB - NOT dBm. Specifically, R1 and R2, do NOT indicate the actual power levels out of the source ports.

How to make receiver measurements

 Press Measure 1

 Then Advanced

 Then choose from the following:

(* ) indicates the Auto-selected source port for the measurement

 Source Port The FieldFox port to provide the source signal. Choose from the

following:

o Auto The FieldFox sets the source port based on the selected receiver.

o Port 1 Select when measuring transmission at B receiver.

o Port 2 Select when measuring reverse transmission at A receiver.

Learn more about Raw Receiver Measurements at the FieldFox Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

Multi-Trace Configurations

In NA Mode you can display multiple traces on the FieldFox screen.

40 FieldFox User’s Guide

x1 1 trace standard configuration

x2 2 traces overlayed on a single graticule

x2H 2 traces on separate horizontal graticules

x3H 3 traces on separate horizontal graticules

X3 3 traces overlayed on a single graticule

x4 4 traces on separate graticules

An x3H configuration. Tr2 is the ACTIVE trace as indicated by the highlighted Tr 2

Trace Setting Notes

 The Frequency Range, IF BW, Resolution, Average, and Output Power settings

are common for all displayed traces.

 All other trace settings, such as measurement, format, and limit lines, are

applied individually to the ACTIVE trace in the same manner as when a single trace is present.

 By default, a marker is created on ALL traces as shown in the above image.

However, they can be created individually by disabling Coupled Markers. Learn more on page 151.

How to select a multi-trace configuration

 Press Trace 6

 Then Num Traces

 Then choose from the following:

The default measurements depend on the options that are installed.

NA (Network Analyzer) Mode 41

How to activate a trace in order to change a setting

 Use the ▲|▼ arrows OR

 Press Trace 6 then select Trace 1, Trace 2, Trace 3, or Trace 4, Only traces

that are shown can be activated.

How to maximize the viewing of the active trace

 Press System 7

 Then Full Screen.

 Press any key to return to the standard display.

Quick Settings

How to view and change Quick Settings

 Press Meas Setup 4 .

 Then Settings.

 Press Next Page and Previous Page to view all settings. If these softkeys are

NOT available, then all available settings fit on one page.

 To change a setting:

o Use the ▲|▼ arrows to highlight a setting.

o Then press Edit. The current setting changes to yellow.

o Some settings require you to press a softkey to change the value. Otherwise,

use the numeric keypad, ▲|▼ arrows, or rotary knob to change the value.

o When finished changing a value, press Done Edit.

 Press Dock Window to relocate the Settings table to a position relative to the

trace window. The Dock Window setting persists through a Preset. Choose from the following:

o Full (Default setting) Only the Settings table is shown on the screen. The

trace window is temporarily not shown.

o Left The Settings table is shown to the left of the trace window.

o Bottom The Settings table is shown below the trace window.

When finished changing ALL settings, press Done to save your settings.

Format

Select the display format in which to present measurement results. This setting can be changed at any time without affecting calibration accuracy.

NOTE Learn more about Display Formats in the FieldFox Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

42 FieldFox User’s Guide

The marker onscreen readout can be changed to formats other than the display format. Learn how to set marker format on page 153.

How to select a NA Format

 Press Measure 1 .

 Then Format [current setting].

 Then choose from the following:

o Log Magnitude Displays magnitude in dB

o Linear Displays positive values only. Y-axis: Unitless (U) for ratioed

measurements; Watts (W) for unratioed measurements.

o VSWR Used mainly for S11 and S22. Displays unitless reflection data.

o Phase Displays phase in degrees. The trace ‘wraps’ every 360 degrees, from

+180 to –180, for easy scaling.

o Smith Used mainly for S11 and S22. Displays series resistance and

reactance.

o More then…

o Polar Used mainly for S11 and S22. Displays magnitude and phase of the

reflection coefficient.

o Group Delay Used mainly for S21 and S12. Displays signal transmission

(propagation) time through a device in seconds. The Group Delay aperture is the current Smoothing aperture. Default is 1.5 % of the X-axis.

o Learn how to set Smoothing aperture on page 46.

o Learn more about Group Delay measurements at the FieldFox

Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

o Unwrap Phase Same as Phase, but without 180 degree wrapping.

NOTE Phase is unwrapped by comparing the phase from one data point to the next. If

the phase difference between two data points is greater than 180 degrees, or if the phase of the first data point is greater than 180 degrees from DC, than the phase measurement is probably NOT accurate. Increase the resolution setting to ensure that the phase measurement is accurate.

Frequency Range

Set the range of frequencies over which you would like to make measurements.

When the frequency range is changed after a calibration is performed, the cal becomes interpolated. Learn more on page71.

How to set Frequency Range

This can be done in two ways:

 Press Freq/Dist

 Then choose from the following:

o Start and Stop frequencies – Specify the beginning and end of the sweep.

NA (Network Analyzer) Mode 43

Scale annotation on the FieldFox screen

· Reference Line = red arrow

· Ref Level = –40 dB

· Ref Position = 1

· Scale = 2 dB per division

o Center and Span frequencies - Specify the center frequency and span of

frequencies (half on either side of center).

 Follow each by entering a value using the numeric keypad, the ▲|▼ arrows, or

the rotary knob.

 After using the ▲|▼ arrows or the rotary knob, press Enter. The increment

setting of the arrows is based on the current span and can NOT be changed in NA Mode.

 After using the keypad, select a multiplier key. Learn about multiplier

abbreviations on page 19.

Scale Settings

Adjust the Y-axis scale to see the relevant portions of the data trace. The Y-axis is divided into 10 graticules.

This setting can be changed at any time without affecting calibration accuracy.

How to set Scale

 Press Scale / Amptd .

 Then choose from the following methods:

1. Autoscale Automatically adjusts the Y-axis to comfortably fit the Min and Max amplitude of the trace on the screen.

2. Autoscale All Autoscales all of the traces on the screen, useful only for multi-trace configurations.

3. Set Scale, Reference Level, and Reference Position

o Scale Manually enter a scale per division to view specific areas of the trace.

o Ref Level Manually set the value of the reference line. Enter a negative

value by pressing Run/Hold (+/-) either before or after typing a value.

o Ref Position Manually set the position of the reference line. Values must be

between 0 (TOP line) and 10 (BOTTOM line)

Electrical Delay

44 FieldFox User’s Guide

Electrical delay is a mathematical function that simulates a variable length of lossless transmission line. Use the electrical delay feature to compensate for the linear phase shift through a device and view only the deviation from linear phase of the device.

You can set the electrical delay independently for each measurement trace. To apply an electrical delay to all measurement traces, use Port Extensions. Learn how on page 50.

Learn how to set Phase formats on page 42.

How to set Electrical Delay

 Press Scale / Amptd

 Then More

 Then Electrical Delay

 Enter a time value using the numeric keypad, the ▲|▼ arrows, or the rotary

knob.

 Press a multiplier key. Learn about multiplier abbreviations on page 19.

Electrical Delay can also be set using the Mkr->Delay feature. Learn how on page

157.

Phase Offset

Phase offset mathematically adjusts the phase measurement by a specified amount, up to 360°. Use this feature in the following ways:

Improve the display of a phase measurement. This is similar to the way you would change the reference level in an amplitude measurement. Change the phase response to center or align the response on the screen.

Emulate a projected phase shift in your measurement. For example, if you know that you need to add a cable and that the length of that cable will add a certain phase shift to your measurement, you can use phase offset to add that amount and simulate the complete device measurement.

You can set the phase offset independently for each measurement trace.

How to set Phase Offset

 Press Scale / Amptd

 Then More

 Then Phase Offset

 Enter a value in degrees using the numeric keypad, the ▲|▼ arrows, or the

rotary knob. Press Enter

Averaging

Averaging helps to reduce the effects of random noise on a measurement. You specify the number of measurements to be averaged. The more measurements averaged, the greater the amount of noise reduction. An average counter is shown in the left edge of the screen as Avg <n> where <n> is the number of measurements that are averaged.

Averaging can be set before or after calibration. When set before calibration, each calibration standard is measured <n> times and averaged. More time is needed to perform the calibration, but there will be less noise in the resulting error terms which means that subsequent measurements will also have less noise. In addition, noise is further reduced by continuing to average after calibration.

NA (Network Analyzer) Mode 45

How to set Averaging

 Press BW 2 .

 Then Average <n> where <n> is the number of measurements to average.

 Enter a value using the numeric keypad. Enter 1 for NO averaging.

 Press Enter .

 Then Average Mode Choose from the following:

o Sweep - Each data point is based on the average of the same data point

being measured over <n> consecutive sweeps. The average counter shows the number of previous sweeps that have been averaged together to form the

current trace. When the counter reaches the specified count, then a ‘running average’ of the last <n> sweeps is displayed.

o Point - Each data point is measured <n> times and averaged before going to

the next data point. On subsequent sweeps, averaging restarts by measuring each data point again <n> times. The average counter is not updated because data is not displayed until all the averages have been applied.

o Point averaging is usually faster than sweep averaging. However, you may

need to increase the Point Average count to obtain the same level of noise reduction as with sweep averaging.

 While averaging is in process, press Sweep 3 then Restart to restart the

averaging at 1.

IF Bandwidth

The FieldFox converts the received signal from its source to a lower intermediate frequency (IF). The bandwidth of the IF bandpass filter is adjustable. Reducing the IF receiver bandwidth reduces the effect of random noise on a measurement. However, narrower IF bandwidths cause longer sweep times.

How to set IF BW

 Press BW 2 .

 Then IF BW

 Then choose from the following:

 10 Hz | 100 Hz | 1 kHz | 10 kHz | 100 kHz

More 30 Hz | 300 Hz | 3 kHz | 30 kHz

Smoothing

Trace smoothing averages a number of adjacent data points to smooth the peakto-peak noise values on a displayed trace. The number of adjacent data points that are averaged is known as the smoothing aperture. Aperture is set by specifying a percentage of the X-axis span.

Trace smoothing does NOT significantly increase measurement time.

Smoothing is used in Group Delay measurements, although it can be used with any NA format EXCEPT Polar or Smith Chart. Learn more about NA Mode formats, including Group Delay, on page 42.

When enabled, Smo appears on the FieldFox screen.

46 FieldFox User’s Guide

How to set Smoothing

 Press BW 2 .

 Then Smoothing ON OFF

 Then Sm. Aperture and enter a value between 0 and 25 (percent) using the

numeric keypad.

 Press Enter

Single or Continuous Measure

This setting can be changed at any time without affecting calibration accuracy.

How to set Single or Continuous

 Press Sweep 3 .

 Then choose one of the following:

o Single Automatically sets Continuous OFF and causes FieldFox to make

ONE sweep, then hold for the next Single key press. Hold is annotated in the upper left corner of the display when NOT sweeping, and changes to an arrow --> while the sweep occurs.

o Continuous Makes continuous sweeps. This is the typical setting when

battery power is not critical.

You can also use Run / Hold +/- to toggle between Single and Continuous.

Resolution (Number of Data Points)

Data points are individual measurements that are made and plotted across the Xaxis to form a trace. Select more data points to increase measurement resolution. However, more data points also takes more time to complete an entire measurement sweep.

When the Resolution is changed after a calibration is performed, the cal becomes interpolated. Learn more on page 71.

How to set Resolution

 Press Sweep 3 .

 Then Resolution.

 Then choose from the following:

101 |201 | 401 | 601 | 801 | 1001 | 1601 | 4001 | 10001.

 Using SCPI, Resolution can be set to ANY number of points between 3 and

10001. See the Programming Guide at http://na.tm.agilent.com/fieldfox/help/

NA (Network Analyzer) Mode 47

Sweep Time

The fastest possible sweep time is always used as the default setting. Use the Min Swp Time setting to slow the sweep time when measuring long lengths of cable.

Learn more at the FieldFox Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

NOTE Measurement speed specifications do NOT apply in Temperature Control Mode.

Learn more on page 13.

How to set Sweep Time

 Press Sweep 3 .

 Then Min Swp Time.

 Enter a value using the numeric keypad.

 Press a multiplier key. Learn about multiplier abbreviations on page 19.

Triggering

External triggering (NA and SA modes ONLY) allows you to initiate a sweep when an external DC voltage is sensed at the Ref In/Trig In connector on the FieldFox top panel. See External Triggering for SA Mode on page 94.

Trigger Source

 Press Sweep 3

 Then Trigger

 Then Trig Source

 Then choose from the following:

o Internal Sweeps are initiated by the FieldFox internal circuitry. When

Sweep is set to Continuous, a new sweep begins automatically when the previous sweep ends.

o External A sweep is initiated on the rising or falling edge of an external TTL

signal at the Ref In/Trig In connector on the FieldFox top panel.

o When the FieldFox is armed for an external trigger signal, Wait is

annotated on the display.

o A sweep can NOT be initiated by an external signal while a sweep is in

progress.

o A sweep can NOT be initiated by an external signal when in HOLD mode.

Learn more about HOLD mode on page 47.

Trigger Slope

Determines which edge of an External trigger signal initiates a sweep.

 Press Sweep 3

48 FieldFox User’s Guide

 Then Trigger

 Then Trig Slope

 Then choose from the following:

o Positive Sweep is initiated by the rising edge of signal at about 1.7 V.

o Negative Sweep is initiated by the falling edge of signal at about 1.0 V.

Output Power

Set the power level out of the FieldFox to High, Low, or manually set power level to a value between High and Low.

For best measurement accuracy, use the Manual power setting at -15 dBm. After calibration, the power level can be decreased for amplifiers, or increased for higher dynamic range.

Caution Power Level settings in this mode will NOT change Power Level settings in other

modes. To help prevent damage to your DUT, use caution when changing modes with your DUT connected to the FieldFox test ports.

How to set Output Power

 Press Meas Setup 4 .

 Then Output Power

o High Sets output power to the maximum achievable power at all displayed

frequencies. Output power is NOT FLAT across the displayed FieldFox frequency span. Please see the FieldFox Specifications (see page 214) for expected power levels.

o Low Sets output power to approximately –45 dBm, FLAT across the

displayed FieldFox frequency span.

o Man (default setting at -15 dBm) Set output power to an arbitrary value,

FLAT across the displayed FieldFox frequency span. If flattened power can NOT be achieved, a warning message and beep occurs. To achieve a flattened output power, reduce the power level or stop frequency.

o Then press Power Level

o Then enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary

knob.

o Press Enter.

System Impedance (Z0)

To accurately view data presented in Smith Chart format, first set the System Impedance.

Learn how to select Smith Chart format on page 42.

Learn how to make 75Ω measurements at the FieldFox Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

NA (Network Analyzer) Mode 49

How to set System Impedance

 Press Meas Setup 4 .

 Then Settings.

 Then scroll to System Z0 and press Edit

 Then type either 50 or 75 and press Enter

Port Extensions

Port extensions allow you to electrically move the calibration reference plane on either port 1 or port 2 after you have performed a calibration.

NOTE FieldFox analyzers do NOT support port extensions for waveguide component

measurements.

Why use Port Extensions

Use port extensions if you are unable to perform a calibration directly at your device because the location is not accessible. Perform a calibration at a convenient place, then use port extensions to compensate for the time delay (phase shift) to the desired reference plane. On the FieldFox, port extensions does not compensate for the loss of the additional electrical length, nor any mismatch errors beyond the calibration reference plane.

Also use port extensions if you have already performed a calibration, and then decide that you need to add a length of transmission line in the measurement configuration. Use port extensions to "tell" the FieldFox that you have added the length to a specific port..

 With S11 and S22 reflection measurements, the FieldFox doubles the port

extension valued that you enter to account for the additional delay in the forward and reverse directions.

 With S21 and S12 transmission measurements, the port 1 and port 2

extensions are added together. This accounts for the total transmission delay going through ports 1 and 2.

Port extensions and Electrical Delay differ in the following ways:

 Electrical delay applies to a specific trace

 Port extensions apply to specific hardware ports

Port Extensions and Electrical Delay can be set independently. When both are set, the delay adds together. Learn more about Electrical Delay on page 44.

How to apply Port Extensions

 Press Meas Setup 4 .

 Then Port Extensions

 Then Port Extensions ON

 Then Port1 Extension

 Then enter time value using the numeric keypad, the ▲|▼ arrows, or the

rotary knob. Press Enter or select a seconds (time) multiplier.

50 FieldFox User’s Guide

You can also set Port Extensions by pressing Meas Setup 4 then Calibration (settings).

While setting Port Extension, the physical length of the extension, at the current Velocity Factor setting, is visible to the right (red box in above image).

Velocity Factor

The electrical delay or port extension value is entered as delay, or electrical length, in units of time.

Entering the velocity factor causes the FieldFox to accurately display the equivalent physical length in meters (NOT available in feet) that corresponds to the entered electrical delay.

Velocity factor is the ratio of the velocity of wave propagation in a coaxial cable to the velocity of wave propagation in free space. This velocity depends on the relative permittivity of the cable dielectric ( r).

Velocity factor = 1/sqrt(εr)

VF = 0.66 corresponds to wave propagation through a polyethylene dielectric.

VF = 1.0 (default setting) corresponds to wave propagation through free space (a vacuum).

How to set Velocity Factor

 Press Meas Setup 4 .

 Then Port Extensions

 Then Velocity Factor

 Then enter a value between 0.1 and 1 using the numeric keypad, then press

Enter.

You can also set Velocity Factor by pressing Meas Setup 4 then Calibration (settings).

Increase Dynamic Range

Dynamic range is the difference between maximum input power to the FieldFox receiver (without compressing the receiver), and the minimum measurable power (noise floor). Measurement accuracy is increased when the DUT response is at least 10 dB above the noise floor. For a measurement to be valid, input signals must be within these boundaries.

NA (Network Analyzer) Mode 51

The following settings will increase the dynamic range of your NA mode measurement.

 Increase Power Level: Press Meas 4 then Output Power High

 Lower the IFBW: Press BW 2 then IF BW

 Increase Averaging: Press BW 2 then Average

The following procedure MAY increase the dynamic range of your NA mode measurement. The results you see will depend on the performance of your DUT.

With an S21 trace active:

1. With RF OUT (port-2) open, press Trace 6 then Math and Memory then

Data->Mem

2. Re-connect the DUT.

3. Press Data Math then Data-Mem

52 FieldFox User’s Guide

Time Domain - Option 010

With NA Mode, Time Domain (Opt 010), frequency information is used to calculate and display measurements with time as the horizontal display axis. The response values appear separated in time allowing a different perspective of the test device's performance and limitations.

NA Mode settings that are NOT unique to Time Domain are documented in the NA Mode chapter on page 38.

In this Chapter

Overview ................................................................. 53

Time Domain (Transform) Settings

Transform Settings Table ..................................... 54

Frequency Range and Points ............................... 55

Stimulus (Mode) ..................................................... 55

Set Frequency Lowpass ....................................... 55

Start/Stop Time ...................................................... 55

Distance Units ........................................................ 56

Window Layout ...................................................... 56

Transform Window ................................................ 56

Line Loss and Velocity Factor ............................. 57

Data Chain .............................................................. 58

Trace Settings

Transform Enable .................................................. 58

Gating Enable ......................................................... 58

Gating Settings

Start, Stop, Center, and Span Gate Times ......... 60

Gating Type ............................................................. 60

Overview

In normal NA Mode operation, the FieldFox measures the characteristics of a test device as a function of frequency. With Time Domain (opt 010), frequency information is used to calculate the inverse Fourier transform and display measurements with time on the horizontal display axis. The response values appear separated in time, allowing a different perspective of the test device's performance and limitations.

The graphic below compares the same cable reflection measurement data in both the frequency and time domain. The cable has two bends. Each bend creates a mismatch or change in the line impedance.

Time Domain - Option 010 53

The frequency domain of an S11 measurement shows reflections caused by mismatches in the cable. It is impossible to determine where the mismatches physically occur in the cable.

The Time Domain response shows both the location and the magnitude of each mismatch. The responses indicate that the second cable bend is the location of a significant mismatch. This mismatch can be gated out, allowing you to view the frequency domain response as if the mismatch were not present. Learn more about gating on page 59.

Markers that are created on a Time Domain trace can be used to pinpoint the distance of the mismatch from the reference plane.

For more information on Time Domain theory, see

http://cp.literature.agilent.com/litweb/pdf/5989-5723EN.pdf

Time Domain (Transform) Settings

You can set and view most of the Time Domain settings on the Transform Settings table.

Transform Settings Table

The following settings are listed in the order they appear on the Transform Settings menu selection.

How to make settings on the Transform settings table

 Press Meas Setup 4 .

 Then Transform

 Then Transform Settings.

 Press Next Page and Previous Page to view all settings.

 To change a setting:

o Use the ▲|▼ arrows or rotary knob to highlight a setting.

o Numeric settings can be changed by pressing numbers using the numeric

keypad. Then press Enter or select a suffix if available.

o Some settings allow you to press Edit to toggle the value. Other settings

require that you then press a softkey to change the value.

o When finished changing a value, press Done Edit.

 Press Dock Window to relocate the Settings table to a position relative to the

trace window. The Dock Window setting persists through a Preset. Choose from the following:

o Full (Default setting) Only the Settings table is shown on the screen. The

trace window is temporarily not shown.

54 FieldFox User’s Guide

o Left The Settings table is shown to the left of the trace window.

o Bottom The Settings table is shown below the trace window.

 When finished changing ALL settings, press Done to save your settings.

Frequency Range and Points

Like CAT mode, all Time Domain measurements are made in the frequency domain and, using Inverse Fourier Transform (IFT), time is calculated. Select the frequency range from which Time Domain measurements are calculated. Increasing the data points will improve measurement resolution. However, more data points will usually result in slower sweep updates.

Set frequency range and points before selecting Stimulus Mode.

Stimulus (Mode)

There are three variations on how the Time Domain transform algorithm is applied to the frequency domain measurement. Each method has a unique application.

 Lowpass Impulse - Highest resolution. Most useful for seeing small responses

in devices that pass low frequencies, such as cables.

 Lowpass Step - Easiest to identify inductive and capacitive discontinuities in

devices that pass low frequencies such as cables.

In both Lowpass modes, frequencies down to DC and negative frequencies are extrapolated. Therefore, when either Lowpass mode is selected, Set Freq.Low Pass is automatically applied to adjust the start frequency. Learn more about Set Frequency Lowpass below.

When the Start Frequency or resolution is changed AFTER selecting a Lowpass mode, then Stimulus mode is set to Band Pass and Transform is disabled.

 Band pass- Easiest method - can be used with any frequency sweep. Most

useful for measuring band limited devices such as filters and DC blocked cables. This mode does NOT show capacitive and inductive reactance. For the same frequency span and number of points, band pass mode has twice the impulse width, which hides closely spaced responses degrading the response resolution.

Set Frequency Lowpass

NOTE This setting is made automatically when either Lowpass mode is selected.

USE ONLY IN LOW PASS MODES. When this setting is made, the start frequency is adjusted to be harmonics of the start frequency. Start frequency is computed by the following formula:

Low Pass Start Frequency = Stop Frequency / Number of points.

Start/Stop Time

The following settings adjust the display resolution, allowing you to zoom IN or OUT on a response. When the start or stop time is updated, they may be automatically adjusted to limit the display to one alias-free response on either side of zero time.

Time Domain - Option 010 55

How to set Start and Stop time

 Press Measure 4

 Then Transform

 Then Transform Start Stop

 Then choose from:

o Start Sets the transform start time.

o Stop Sets the transform stop time.

NOTE Zero (0) seconds is always the calibration reference plane. Negative values are

useful if moving the reference plane.

Distance Units

When markers are present on a Time Domain trace, marker X-axis values are shown both in units of time (seconds) and distance. Select the units in which the marker distance data is presented.

Distance Units are also used when setting Time Domain Line Loss. Learn more on page 57.

Choose from: m (meters), or Feet.

Window Layout

This setting is used to create additional traces, or select a new layout for traces that are already created,

Choose from: x1, x2, x2H, x3H, x4.

Learn more about multi-trace configurations on page 40.

Transform Window

There are abrupt transitions in a frequency domain measurement at the start and stop frequencies, causing overshoot and ringing in a Time Domain response. The Window setting reduces the abruptness of the frequency domain transitions. This causes you to make a tradeoff in the Time Domain response.

The Window setting applies to ALL traces.

56 FieldFox User’s Guide

1. Window

Min

Medium

Max

2. Percent

100

3. Kaiser Beta

6.50

13.00

4. Impulse

Width

100.455 ps

168.501 ps

231.284 ps

How to make Window setting

 Press Measure 4

 Then Transform

 Then More

 Then Transform Window

 A settings table appears that allows you to navigate and select the following

settings. These settings are made exactly like those made on the Transform Settings table. Learn how on page 54.

NOTE Any of the following four methods can be used to make this same Window

setting. Impulse Width values are calculated from the frequency span and Kaiser Beta value.

Line Loss and Velocity Factor

By default, the FieldFox does NOT correct Time Domain measurements to account for the inherent loss of a cable. However, to make more accurate measurements, Line Loss and Velocity Factor should be considered.

About Velocity Factor and Line Loss

o Velocity Factor is a property of the physical material of a cable. A VF of 1.0

corresponds to the speed of light in a vacuum, or the fastest VF possible. A polyethylene dielectric cable has VF = 0.66 and a cable with PTFE dielectric has VF = 0.7.

o Line Loss is specified in dB/m (or ft). In addition to the length of the cable,

loss is also directly proportional to the frequency of the signal that passes through the cable.

The following is an example showing how Line Loss works:

The DUT is a 100 meter transmission cable. The Line Loss value is .1 dB/meter. This means that a signal traveling ONE WAY through the cable will lose 10 dB of power (100 m * .1dB/m). Because the FieldFox performs this measurement with 1 port, the test signal travels down the cable and then back, for a total loss of 20 dB.

For the purpose of illustrating this point, connect an OPEN to the end of the cable – a maximum-sized fault - for 100% reflection of the 300 MHz test signal.

Time Domain - Option 010 57

Data Chain

This setting, available only on the Transform Settings Table, reverts to Standard when the FieldFox is Preset. Choose from the following:

 Standard – The normal FieldFox data processing chain. Transform

calculations are performed AFTER error correction and trace math.

 8510 – The data processing chain used by the Agilent 8510 network analyzer.

Transform calculations are performed BEFORE error correction and trace math. Learn more at the FieldFox Supplemental Online Help website:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

Trace Settings

The following two settings apply to specific traces.

Transform Enable

Enable Time Domain transform for the specific trace.

 Select the trace.

 Press Measure 4

 Then Transform

 Then choose from:

o On Trace displays Time Domain data.

o Off Trace displays frequency domain data.

Gate Enable

Enable Gating for the specific trace.

 Select the trace.

 Press Measure 4

 Then Transform

 Then choose from:

o On Trace displays Time Domain data.

o Off Trace displays frequency domain data.

58 FieldFox User’s Guide

Gating

Perhaps the most beneficial feature of Time Domain transform is the Gating function. When viewing the Time Domain response of a device, the gating function can be used to "virtually" remove undesired responses. You can then simultaneously view a frequency domain trace as if the undesired response did not exist. This allows you to characterize devices without the effects of external devices such as connectors or adapters.

Gating is best performed while viewing a Time Domain trace. Then, either disable Transform, or separately view a frequency domain trace to see the trace with the gated effects removed.

NOTE When a discontinuity in a test device reflects energy, that energy will not reach

subsequent discontinuities. This can "MASK", or hide, the true response which would have occurred if the previous discontinuity were not present. The Gating feature does NOT compensate for this.

The following image shows how gating can affect measurement results.

All 4 traces show the same S11 measurement.

Trace 1 shows the frequency response without gating enabled.

Trace 2 shows the transform response without gating enabled.

Trace 3 shows the transform response with gating enabled.

Trace 4 shows the frequency response with gating enabled.

How to make Time Domain Gating settings

 Press Measure 4

 Then Transform

 Then Gating

 Then choose from:

o On Gating is being performed.

o Off Gating is NOT being performed.

Time Domain - Option 010 59

Gate Shape

Passband Ripple

Sidelobe

Levels

Cutoff Time

Minimum Gate Span

Minimum

0.1 dB

-48 dB

1.4/Freq Span

2.8/Freq Span

Normal

0.1 dB

-68 dB

2.8/Freq Span

5.6/Freq Span

Wide

0.1 dB

-57 dB

4.4/Freq Span

8.8/Freq Span

Maximum

0.01 dB

-70 dB

12.7/Freq Span

25.4/Freq Span

Start, Stop, Center, and Span Gate Times

These settings specify the time in the trace to be gated (in or out). The gate times can be specified using either Start and Stop or Center and Span.

 Press Gating Start/Stop

 A settings table appears that allows you to navigate and select the following

settings. These settings are made exactly like those made on the Transform Settings table. Learn how on page 54.

Gating Type

This setting defines the type of filtering that will be performed for the gating function. The gate start and stop flags on the display point toward the part of the trace you want to keep.

 Choose from the following:

o Bandpass - KEEPS the responses within the Gating Start and Stop times.

o Notch - REMOVES the responses within the Gating Start and Stop times.

Gating Shape

This setting defines the filter characteristics of the gate function. Choose from Minimum, Normal, Wide, Maximum.

Time domain Gate Shape setting

Cutoff time is the time between the stop time (-6 dB on the filter skirt) and the peak of the first sidelobe.

 T1 is the gate span, which is equal to the stop time minus the start time.

 T2 is the time between the edge of the passband and the 6 dB point,

representing the cutoff rate of the filter.

 T3 is the time between the 6 dB point and the edge of the gate stopband.

60 FieldFox User’s Guide

For all filter shapes T2 is equal to T3, and the filter is the same on both sides of the center time.

Minimum gate span is twice the cutoff time. Each gate shape has a minimum recommended gate span for proper operation. This is a consequence of the finite cutoff rate of the gate. If you specify a gate span that is smaller than the minimum span, the response will show the following effects:

 distorted gate shape that has no passband

 distorted shape

 incorrect indications of start and stop times

 may have increased sidelobe levels.

Time Domain - Option 010 61

Calibration for NA, CAT, and VVM Modes

Calibration removes the systematic errors that are associated with measurements in NA, CAT, and VVM Modes. Key presses are identical in all of these Modes.

In this Chapter

Why and When to Calibrate ................................. 62

Definitions .............................................................. 62

CalReady ................................................................. 63

How to Perform a Calibration ............................. 64

QuickCal .................................................................. 64

Mechanical Cal ....................................................... 66

Response Cal .......................................................... 68

View Cal................................................................... 69

Calibration Type .................................................... 69

Enhanced Response Optimization ...................... 71

Interpolation ........................................................... 71

Questionable Accuracy ......................................... 72

Compatible Mode Calibrations ............................ 72

Save a Calibration ................................................. 72

CalReady Properties .............................................. 72

Verify Calibration .................................................. 73

Calibration Method Summary ............................. 74

See Also

Learn How to Make 75 ohm Measurements at the FieldFox Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

Why and When to Calibrate

There are well-defined and understood systematic errors that are measured and calculated during the calibration process. These errors are caused by leakage signals inside the FieldFox, by the frequency response of the FieldFox receivers, and by reflections inside the FieldFox that interact with the DUT. After calibration, these errors are removed from subsequent measurements.

To maintain highest measurement accuracy, perform a new calibration when any of the following changes occur:

 When any of the following measurement settings change: Frequency Range,

Power Level, IF BW, and Resolution. Therefore, make these measurement settings before calibrating. Increased Averaging, lower IF BW, and higher Resolution all cause slower sweeps and slower calibration times. Learn about Interpolation and Questionable Accuracy on page 71.

 When the FieldFox temperature changes more than about 10°F (5°C). Learn

how to monitor the internal temperature on page 12.

62 FieldFox User’s Guide

 When the connection to the DUT changes, requiring a different jumper cable or

adapter.

Definitions

DUT (Device Under Test) The cable, antenna, transmission line, amplifier, or anything else that is connected to the FieldFox that is to be measured.

Calibration Standards - OPEN, SHORT, LOAD, and THRU

 OPEN, SHORT, and LOAD are ‘reflection’ standards that are used during

calibration. When an RF signal ‘hits’ these components, the signals are

reflected in a predictable manner. These components can also be used to terminate a DUT port during some measurements.

o SHORT and OPEN standards both cause 100% of an RF signal to be reflected.

The difference between these two standards is what happens to the phase of the reflected signal, which is beyond the scope of this discussion. Although an OPEN standard is a precision component, simply leaving nothing connected at the end of a cable can be a reasonable substitute for an OPEN.

o A LOAD standard absorbs almost ALL of the incident signal and very little

signal is reflected back to the source.

 A THRU standard is used during some calibration steps to connect PORT 1 to

PORT 2 in place of the DUT. A Flush THRU connection can be made when cables that connect with the DUT can mate with each other. Learn more on page 69. Otherwise, any reasonably short cable can be used as a THRU standard.

Calibration Reference Plane is the point (or points) at which the DUT and cal standards are connected during a calibration. This can be at the FieldFox test port connectors, or at the end of jumper cables or adapters.

CalReady

Every FieldFox contains a factory calibration that was performed at the port 1 and port 2 connectors, with -15 dBm input power, over the entire frequency range of the FieldFox using a number of data points that allows reasonable interpolation over the FieldFox frequency range.

This calibration, known as CalReady, allows you to immediately make measurements of a DUT that is connected directly at the test ports (PORT 1 and/or PORT 2). CalReady corrects measurements when the FieldFox is turned ON and when a measurement is created with no other correction in place.

When measuring a DUT using a jumper cable or adapter - NOT a direct connection to a test port connector – then a QuickCal or Mechanical Cal is recommended. CalReady can also be used to check the integrity of the jumper cable that is attached to the test ports.

CalRdy is shown when a measurement is corrected using CalReady.

You can change the properties of the CalReady calibration. Learn more on page

72.

Learn how to see when your factory CalReady calibration was performed on page

186.

Calibration for NA, CAT, and VVM Modes 63

How to Perform a Calibration

 In CAT, NA, or VVM Mode, press Cal 5.

The following appears:

Choose Calibration Method screen

Response Cal – Used to quickly calibrate ONE measurement using mechanical standards. Measurement accuracy is generally low. Learn more on page 68.

Quick Cal – Using built-in cal standards and CalReady, quickly and accurately calibrate measurements when using a jumper cable or adapter to connect the DUT to the FieldFox test ports. Learn more on page 64.

Mechanical Cal – Using mechanical cal standards from a cal kit, perform an accurate calibration at one or both test ports, adapters, or jumper cables. Full 2port mechanical calibration is the most accurate calibration available with FieldFox. Learn more on page 66.

Cal ON OFF – Turns ON and OFF the effects of the user calibration that you performed. The OFF state reverts to CalReady which can never be turned OFF.

View Cal – Shows the properties of the current calibration. Learn more on page

69.

More – Learn about Cal Ready Properties on page 72.

NOTE Press Esc at any time to end the calibration process.

QuickCal

QuickCal is ideal for a quick and simple calibration of the measurement when using a jumper cable or adapter to connect the DUT to the FieldFox test ports. QuickCal corrects for phase shift, time delay, and loss of adapters or jumper cables.

QuickCal does not require a specific Cal Kit and is a very simple calibration. If the highest accuracy is required, a mechanical calibration with a high quality calibration kit is recommended.

QuickCal is designed and most accurate when calibrating for DUTs fitted with Type-N and 7/16 connectors.

If the DUT has different connectors, such as 3.5 mm (male) or SMA male connectors, QuickCal can still be used by selecting 'Other' connector. However, the accuracy of QuickCal with ‘Other’ connectors is not specified.

64 FieldFox User’s Guide

If the DUT has 3.5 mm-female or SMA-female connectors, QuickCal is NOT recommended. For accurate and repeatable measurements of devices with female

3.5 mm or SMA connectors, use mechanical calibration.

Important QuickCal Notes

 7/16 connectors can be used with QuickCal ONLY up to 6 GHz.

 Type-N 75 Ohm can be used with QuickCal ONLY up to 3 GHz.

 QuickCal cannot be used with waveguides, or if the test fixture or test setup

(before DUT) includes an attenuator.

How to perform a QuickCal

 In CAT, NA, or VVM Mode, press Cal 5

 Then QuickCal

o Press Change DUT Connectors to select the correct connector types that

are on your DUT. Although there is no Cal Kit required, selecting the connector type (limited to Type-N and 7/16) and gender from the list provides an accurate OPEN model which means a more accurate calibration. If the DUT connector type is not listed, select Unknown/Other.

o The connector choices that are offered depend on the frequency range. For

example, if you have selected a frequency range that exceeds 18 GHz, the only connector options you will be presented with in QuickCal are 'other 50 ohm' or 'other 75 ohm'. This is because 3.5 mm connectors, which go beyond 18 GHz, are not supported with QuickCal.

 For each DUT port:

o Select the connector type of the DUT using the ▲|▼ arrows or rotary knob.

o Press Change Gender to change the gender of the DUT connector.

o Then press Next… to make the selection.

 Select/Change Cal Type. The FieldFox always RECOMMENDS a Cal Type that

will quickly and accurately calibrate all of the displayed S-parameters. The other Cal Types that are listed will NOT necessarily calibrate all of the displayed S-parameters. Learn more about Cal Types on page 69.

o Using the ▲|▼ arrows or rotary knob, select a Cal Type, then press Select

and Finish.

 Press Start Calibration

No Connection

 Disconnect the DUT from the FieldFox.

 If a jumper cable or adapter is required to connect the DUT to the FieldFox,

connect those components to the FieldFox test ports connectors. The effects of those components will be measured and removed during the calibration, and only the effects of the DUT will be displayed in the measurement results. These should be high-quality components!

 Do NOT connect anything at the cal reference plane where the DUT connects.

 Press Measure

Calibration for NA, CAT, and VVM Modes 65

Optionally Connect Load(s)

 Connect a Load standard at the point where the DUT will be connected and

press Measure under the following conditions:

o When a jumper cable has too much loss. If a ‘Cal Failed’ error appears and

you skipped the Load measurement, then perform the Cal again but measuring the Load.

o When your DUT has high return loss such as the reject band of a filter. Then

measuring the load improves accuracy. Even with the optional Load, phase accuracy begins to degrade when the return loss is greater than about 20dB.

 Press Skip Step in all other cases and when making DTF measurements.

Measuring a load would do little to improve accuracy.

Connect THRU (Not used for 1-port cals)

 Connect port 1 to port 2, either by mating the connectors that attach to the

DUT (Flush THRU), or by using a short jumper cable. Learn more about Flush THRU on page 69. Then press Measure.

 Press Finish.

CAL ON Q is shown on the screen for all displayed measurements that are

corrected with QuickCal.

Using QuickCal with a Long Jumper Cable

QuickCal requires sufficient frequency resolution to adequately characterize the jumper cable (cable between the instrument port and the DUT). QuickCal may automatically acquire more points for longer jumper cables, resulting in longer calibration times.

QuickCal is also limited in how much jumper cable loss it can tolerate. If QuickCal without the load is failing, then measure the load during the QuickCal to see if that resolves the issue.

Mechanical Cal

Mechanical Calibration is performed using discrete standards from a Cal Kit. Several Cal Kit definitions are built into the FieldFox.

NOTE Visit www.agilent.com/find/fieldfoxsupport to see a complete list of supported

Cal Kits. Also at this website, download DataLink software that allows you to edit Cal Kit definitions or add a new Cal Kit.

Mechanical Cals are extremely accurate when performed using the correct Cal Kits with standards that are clean and in good repair, and when using correct connection procedures.

How to perform a Mechanical Cal

 Disconnect the DUT from the FieldFox.

 If a jumper cable or adapter is required to connect the DUT to the FieldFox,

then connect those components to the FieldFox connectors. The effects of those components will be measured and removed during the calibration, and only the effects of the DUT will be displayed in the measurement results. These should be high-quality components!

66 FieldFox User’s Guide

 In NA, CAT, or VVM Mode, press Cal 5.

 Then Mechanical Cal

This page summarizes the Mechanical Cal to be performed and allows you to make changes. For best results, review the screen and make changes in the following order:

1. S-parameters – Verify that these are all of the S-parameters that you want calibrated. If not, press Esc to terminate the calibration process, then return to the Trace menu to display all of the traces to be calibrated. Learn how on page 40.

2. DUT Connectors – For each DUT port that is shown, verify the correct type and gender of the DUT connector. If a DUT port is not shown, then that port is not included in the list of S-parameters to be calibrated.

3. Cal Kit - Verify the correct Cal Kit for each DUT port to be calibrated. See a list of supported Cal Kits in the FieldFox Data Sheet. Learn more on page

214.

If the DUT connector type, gender, or Cal Kit is NOT correct for the DUT ports to be calibrated, then:

o Press Change DUT Connectors to select the correct connector types that

are on your DUT.

o For each port:

o Use the ▲|▼ arrows or rotary knob to change the DUT connector type.

o Press Change Gender to change the gender of the DUT connector.

o Then press Next… to make the selections.

o For each port:

o Use the ▲|▼ arrows or rotary knob to select the Cal Kit that you have,

and are going to use, for the specified ports.

o Then press Next… to make the selection.

Calibration for NA, CAT, and VVM Modes 67

4. Calibration Type - The FieldFox always RECOMMENDS a Cal Type that will quickly and accurately calibrate all of the displayed S-parameters. Change from the RECOMMENDED Cal Type ONLY if you understand the implications. Learn more about Cal Types on page 69.

To select a different Cal Type:

o Press Change Cal Type.

o Then using the ▲|▼ arrows or rotary knob, select a Cal Type,

o Then press Select and Finish.

Begin Calibration

 Press Start Calibration.

NOTE If an error appears (“Failure to compute calibration steps…”), check to ensure

that the frequency range of the Cal Kit covers the frequency range of the measurement. You can verify the frequency range of your Cal Kit at:

www.agilent.com/find/fieldfoxsupport, Click Cal Kits.

 Follow the Cal Wizard prompts. Connect the specified standard at the point

where the DUT will be connected, then press Measure.

 At any time, press Back to re-measure a standard if you feel it was not

properly connected.

 Press Finish to complete the calibration.

CAL ON U is shown on the screen for all displayed measurements that are

corrected with the Mechanical Cal.

Response Cals

Response Cals are used to quickly calibrate the magnitude and phase of a measurement using mechanical standards. Measurement accuracy is generally low. Use a Response Cal to make quick measurements when using a jumper cable to connect the DUT to the FieldFox. Otherwise, CalReady is usually more accurate.

NOTE You can perform a Response Cal for either: S11, S22, or S21 AND S12.

When prompted, choose a standard based on the displayed measurements to be calibrated. For example, to calibrate S11, connect either an OPEN or SHORT standard to the port 1 reference plane.

Normalize uses a THRU standard or cable between port 1 and port 2 to cal an S21 and S12 Transmission measurement (NA Mode) and a 2-port Insertion Loss measurement (CAT Mode). In VVM Mode, this is performed using Zero.

How to perform a Response Cal

 Select the measurements to be calibrated. See the relevant Mode (NA, CAT, or

VVM) for measurement selections.

 Press Cal 5 then Response Cal

 For 1-port measurements:

o Select either Open Response or Short Response for the port to be

calibrated. Port 2 may require an option.

68 FieldFox User’s Guide

o Connect an OPEN or SHORT standard to the specified port and press

Measure

 For 2-port measurements:

o Select Normalization

o Connect a short, high-quality, phase stable cable between the FieldFox port 1

and port 2 connectors, then press Measure

NOTE With a Normalization Cal, all subsequent insertion loss measurements are made

relative to the insertion loss of the THRU cable. For example, if you use a cable with 1 dB of loss, then after Normalization, the display will show 0 dB of loss with this cable in place. Therefore, for highest accuracy, when measuring the DUT also attach the cable that was used in the normalization cal.

 Press Finish.

 Connect the DUT.

CAL ON U is shown on the screen when a Response Cal is correcting ONLY the

appropriate measurement.

View Cal

From the Choose Calibration screen (page 64), press View Cal to see the following screen:

The top box shows the properties of the current calibration that you performed and the displayed S-parameters that it is correcting.

The bottom box shows the S-parameters that are displayed but NOT corrected by the current performed calibration, but rather the CalReady calibration. Learn more about CalReady on page 63.

Calibration Type

The FieldFox simplifies the calibration process by recommending the most accurate and efficient calibration type based on the displayed S-parameters.

However, there may be times when you may want a little more accuracy or a little faster sweep time. The following information can help you learn about the various calibration choices.

Calibration for NA, CAT, and VVM Modes 69

Non-insertable DUT – A device whose connectors could NOT mate together. They either do not have the same type of connector or they have the same gender. This also means that the test port cables could NOT mate together as in the above diagram.

Insertable DUT – A device whose connectors could mate together. They have the same type of connector and opposite or no gender. This also means that the test port cables could mate together, as in the above diagram.

Definitions:

Defined THRU – A THRU standard for which there is a Cal Kit definition such as in the 8551xA Cal Kits.

Flush THRU – When the test port cables mate together when measuring an

Insertable DUT. Flush THRU is also a Defined THRU with a definition of zero loss and zero length.

Sweep Directions – Both FULL 2-Port Cals listed below result in correction that requires background measurements sweeps in both directions, regardless of the displayed measurements. The displayed traces are updated at a slower rate than Enhanced Response and 1-port calibrations, which require sweeps in one direction only.

1-Port (OSL)

DUT: Not Applicable

S-parameters Corrected: S11 or S22

Standards: OPEN, SHORT, LOAD

Sweeps in ONE direction.

FULL 2-Port (May require an option).

Most comprehensive calibration. Corrects all S-parameters.

DUT: Non-Insertable or Insertable

Standards: OPEN, SHORT, LOAD on BOTH ports. Any THRU between ports.

For more information on the Unknown Thru process, see the FieldFox Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

Sweeps in BOTH directions.

FULL 2-Port (QSOLT) – Mechanical Cal ONLY (May require an option).

Quicker to perform than Full 2-port. Corrects all S-parameters.

DUT: Insertable only

Standards: OPEN, SHORT, LOAD on port 1. Flush THRU between ports.

Sweeps in BOTH directions.

70 FieldFox User’s Guide

Enhanced Response Cal - Forward OR Reverse (May require an option)

Faster measurements than Full 2-Port.

DUT: Non-Insertable or Insertable

S-parameters Corrected: S21 and S11 (Forward) OR S12 and S22 (Reverse)

Standards: OPEN, SHORT, LOAD on ONE port. Defined THRU between ports.

Sweeps in ONE direction.

NOTE Also select an Enhanced Response Optimization. Learn more on page 71.

TRL – Mechanical Cal ONLY.

Potentially better accuracy than Full 2-port. Corrects all S-parameters.

DUT: Non-Insertable or Insertable

Standards: Thru, Reflect, Line or variations of these. A TRL Cal Kit MUST be selected to see this Cal Type.

Sweeps in BOTH directions.

Learn more about TRL Calibration in the Supplemental Online Help:

http://na.tm.agilent.com/fieldfox/help/FieldFox.htm.

Enhanced Response Optimization

When Enhanced Response Cal Type is selected, either for one calibration or for CalReady, this setting optimizes the calibration based on the type of DUT being measured. See also: CalReady Properties on page 72.

This setting does NOT survive Preset.

 Press Cal 5 then More

 Then Enh.Response

 Then choose from:

o Non-Reciprocal (default) An amplifier is a Non-Reciprocal device because it

has gain in the forward direction, and very high loss (isolation) in the reverse direction. This choice provides the best correction for non-reciprocal devices, and reasonable correction for reciprocal devices.

o Reciprocal A reciprocal DUT is a device in which the insertion loss through

the device is similar in both the forward (S21) and reverse (S12) directions. A cable is a reciprocal device. This choice provides the best correction for reciprocal devices. However, S11 measurements on non-reciprocal devices will appear to have more return loss than the non-reciprocal choice.

Interpolation *

Highest measurement accuracy is achieved when the frequency range or resolution settings remain the same during the measurement as when the FieldFox was calibrated. If these settings change after performing a calibration, the FieldFox will interpolate the calibration so that VERY accurate measurements continue to be made.

Interpolated Calibrations are only slightly less accurate than a calibration performed at the measurement settings. Learn more about the relative accuracy of FieldFox calibrations on page 74.

Calibration for NA, CAT, and VVM Modes 71

When a calibration that you performed is being interpolated, an asterisk is added to the Cal annotation. For example: Cal ON U* is shown on the screen when the current Response or Mechanical cal is being interpolated. An * is never added to a CalRdy.

Cal ON ? – Questionable Accuracy

When the Output Power, Interference Rejection, or IF BW (NA Mode ONLY) setting is changed AFTER performing a calibration, a question mark is added to the Cal annotation. For example: Cal ON Q?. is shown on the screen when the current QuickCal is being interpolated. An ? is never added to CalRdy.

The resulting measurement accuracy depends on how much the setting has changed. For highest accuracy, recalibrate using the new settings.

Compatible Mode Calibrations

The FieldFox can have only ONE calibration present for all modes (except CalReady). Calibrating in one mode will overwrite calibrations for other modes.

Because NA, CAT, and VVM modes are very similar, a calibration that is performed in one mode can also be applied in the other modes.

To apply a Cal that was performed in a different mode, press Cal 5 then select

Cal ON.

Save the Calibration

After performing any type of calibration, you can save the FieldFox settings along with the calibration into a STATE (*.sta) file. These settings and calibration can then be recalled as necessary. To learn how, see Saving and Recalling Files on page 164.

CalReady Properties

There are several factory CalReady calibrations on every FieldFox. These can be selected based on the type of DUT that you measure most often, and the compromise that you prefer to make between measurement speed versus measurement accuracy. Remember, CalReady was performed at the test ports. Therefore, a CalReady calibration is most accurate when the DUT is connected to the test ports. Learn more about CalReady on page 63.

This setting does NOT survive Preset or Power ON/OFF.

 Press Cal 5 then More

 Then CalRdy

 Then choose from:

o 2-Port Cal (default) Corrects all four S-parameters. Requires a forward and

reverse sweep, which causes slower trace measurements. Learn why on page

69.

o Enh Response Corrects forward (S21 and S11) and reverse (S12 and S22)

measurements separately. Therefore, when measurements in only one direction are required, this choice provides faster trace measurements than a full 2-port cal. Also choose an Enhanced Response Optimization. Learn more on page 71.

72 FieldFox User’s Guide

To find the best choice for your DUT:

 Press Preset then Preset.

 Select the appropriate S-Parameter and other settings (frequency range,

resolution, and so forth).

 Press Trace 6 then Math and Memory then Data->Mem.

 Press Data & Memory.

 Press Cal 5 then More

 Select a CalReady Cal to compare with the current setting.

 Press Esc to exit the cal menu.

 View the differences in the two traces.

Verifying Calibration and Jumper Cable Integrity

After calibrating, it is important to verify that the calibration is good. When using a jumper cable, also verify that the cable is of high quality.

Verify a Calibration

 Connect a LOAD standard at the calibration reference plane (where calibration

standards were connected). This may be at the end of the jumper cable or at FieldFox PORT 1 connector.

 In CAT Mode, select Return Loss.

 In NA Mode, select S11 with Log Mag format.

 For frequencies lower than 9 GHz, observe the trace on the FieldFox screen:

o Lower than 35 dB indicates a GOOD calibration.

o Higher than 0 dB indicates that you should recalibrate.

Verifying Phase Accuracy

 Connect a LOAD standard at the calibration reference plane (where calibration

standards were connected).

 In NA Mode, select a S11 Reflection with Polar or Smith Chart format.

 Because all LOAD standards have delay, you should see a small amount of

phase rotation as a function of frequency. In general, the measurement result should agree with the characteristics of the calibration standard.

Test the Jumper Cable

With the LOAD standard still connected, move the jumper cable while observing the trace.

 If the measurement trace is relatively stable, the jumper cable is of good

quality.

 If you observe significant movement in the peaks of the measurement trace

when moving the cable (>5 dB), the jumper cable may need to be replaced.

Calibration for NA, CAT, and VVM Modes 73

Calibration Method Summary

 Mechanical Full 2-port Cal is ALWAYS the most accurate Cal method. The

quality of a Mechanical Cal is completely dependent on the quality of the OPEN, SHORT, LOAD standards and the quality of the standard connections. Use the correct high quality standards to ensure the most accurate calibration.

 QuickCal is ideal for DTF measurements. QuickCal should be performed when

good accuracy is required and when using a jumper cable or adapter.

o QuickCal is NOT recommended when the DUT has 3.5 mm-female or SMA-

female connectors.

o Even with the optional Load, phase accuracy begins to degrade when the

return loss is greater than about 20dB.

 CalReady is accurate ONLY when the DUT is connected at the test ports and

most accurate at room temperature.

 For highest accuracy, a new QuickCal or Mechanical Cal should be performed:

o When the temperature changes more than about 10°F (5°C)

o When the connection to the DUT requires a different jumper cable or

adapters.

o When any of the following measurement settings change: Frequency Range,

Power Level, IF BW, and Resolution.

74 FieldFox User’s Guide

SA (Spectrum Analyzer) Mode

SA Mode measures signals at the SA RF IN connector.

SA Mode measurements require NO calibration.

For a comprehensive SA mode tutorial, see Spectrum Analysis Basics (App Note

150) at http://cp.literature.agilent.com/litweb/pdf/5952-0292.pdf

Carrier with 5 kHz frequency modulation and deviation of 1 kHz

In this Chapter

Frequency Range ................................................... 77

Radio Standard ...................................................... 78

Channel Selection .................................................. 79

Scale and Units ...................................................... 80

External Gain ......................................................... 81

Attenuation and Preamp Control ....................... 81

Check for Compressed Measurements ............... 83

Field Strength Measurements .............................. 83

Tune and Listen ..................................................... 86

Independent Source .............................................. 86

Resolution Bandwidth .......................................... 86

Video Bandwidth ................................................... 90

Sweep Type ............................................................. 91

IF Output ................................................................. 91

Sweep Acquisition ................................................. 92

SA display with markers

SA (Spectrum Analyzer) Mode 75

Zero Span Measurements ..................................... 93

Triggering ................................................................ 94

FFT Gating (Option 238) ...................................... 97

Single/Continuous/Restart .................................. 98

Points ....................................................................... 98

Trace Display States .............................................. 99

Average Type .......................................................... 99

Average Count ...................................................... 100

InstAlign Amplitude Alignment ........................ 100

RF Burst Alignment............................................. 101

Detection Method ................................................. 102

Display Line .......................................................... 103

Noise Marker ........................................................ 103

Band/Interval Power Marker ............................. 104

Frequency Counter at Marker ........................... 105

Audio Beep at Marker Power ............................ 105

Channel Measurements ...................................... 106

o Channel Power

o Occupied Bandwidth

o Adjacent Channel Power Ratio

See Also

Interference Analyzer

Spectrogram Display ........................................... 115

Waterfall Display ................................................. 118

Record / Playback ................................................ 119

Optional settings

Markers .................................................................. 148

Limit Lines ............................................................ 158

Save Measurement Settings and Results ......... 164

SA Mode Settings

Select SA Mode before making any setting in this chapter.

Because there is no calibration, these settings can be made in any order.

How to select SA Mode

 Press Mode_ .

 Then SA.

76 FieldFox User’s Guide

Frequency Range

The X-axis frequency range determines the frequencies that are measured for each sweep. The default Start frequency is 0 Hz. However, the Start frequency can be set as low as –100 MHz. The internal LO of the FieldFox can be seen at 0 Hz, which will mask signals that may be present.

NOTE Although the start frequency can be set as low as -100 MHz, amplitude accuracy

is specified above 100 kHz. Below 100 kHz, frequency accuracy is maintained, but amplitude accuracy is degraded.

The frequency range of the measurement can be changed using the following methods:

 Set Center and Span frequencies

 Set Start and Stop frequencies

 Toggle between Zero and Last selected span

 Set Full Span of the FieldFox

 Using Channel selection. Learn how on page 79.

 Using Marker -> Center (frequency). Learn how on page 153.

How to set Frequency Range

 Press Freq/Dist .

 Then choose from the following:

o Center and Freq Span frequencies. This is the most common method of

entering frequency range. Enter the frequency of interest. The Center frequency is at the exact center of the X-axis. The Frequency Span places half of the frequency range on either side of center. When the Center and Frequency Span values are entered, then the X-axis annotation on the screen shows the Center and Span frequencies.

o Start and Stop frequencies. Start is the beginning of the X-axis and Stop is

the end of the X-axis. When the Start and Stop frequencies are entered, then the X-axis annotation on the screen shows the Start and Stop frequencies.

 Follow each of these by entering a value using the numeric keypad, the ▲|▼

arrows, or the rotary knob.

 When using the ▲|▼ arrows, press Enter . The increment setting of the arrows

is based on the current span. This can be changed in SA Mode. See How to change frequency step size below.

 After using the keypad, select a multiplier key. Learn about multiplier

abbreviations on page 19.

Two more ways to change the frequency range

 Press Freq/Dist .

 Then choose from the following:

o Zero/Last Span Each key press toggles the frequency span between 0 Hz

and the last specified frequency span. Learn more about Zero Span on page

93.

o More

SA (Spectrum Analyzer) Mode 77

o Then Full Span Selects the entire frequency span of the FieldFox. The

Center frequency is set automatically.

How to change frequency step size

When using the ▲|▼ arrows to change any of the frequency settings, the size of the frequency step can be changed.

 Press Freq/Dist

 Then More

 Then CF Step Auto Man

o Auto Each press of the ▲|▼ arrows increments or decrements the value by

1/10th (one division) of the current frequency span. Note: To change this setting from Man to Auto, press CF Step twice.

o Man Type a step size value using the numeric keypad, then select a

multiplier key. Learn about multiplier abbreviations on page 19.

Radio Standard

A Radio Standard is a collection of settings that are applied to the FieldFox for specific RF protocols. When a Radio Standard is applied, the FieldFox frequency and channel settings change to that of the standard.

By default, the FieldFox locates the center frequency of the standard in the middle of the screen and sets the frequency span to cover all of the Uplink and Downlink frequencies. The selected Radio Standard name appears in the center of the screen below the X-axis.

After a Radio Standard has been selected, the frequency range can be changed by selecting channel numbers rather than frequency. Learn how on page 79.

When a Channel Measurement is selected such as ACPR, other relevant settings will be changed such as Integration BW. Learn more about Radio Standards and Channel Measurements on page 106.

How to select a Radio Standard

 Press Measure 1 OR Freq/Dist then More

 Then Radio Standard

 Then select a standard using the ▲|▼ arrows or rotary knob and press Enter .

Custom Radio Standards

Your own custom Radio Standards can be imported into the FieldFox. Custom standards are created in *.csv (spreadsheet) format.

A template and instructions for creating your custom Radio Standard is at:

http://na.tm.agilent.com/fieldfox/help/Reference/CustomRadioStandard.htm

Once imported, the *.csv file is stored in the FieldFox \User Data\ folder. The custom Radio Standards are read and presented at the top of the list of internal Radio Standards.

78 FieldFox User’s Guide

How to Import and Delete a Custom Radio Standard

First, press Save/Recall and select the Device from which the Radio Standard will be read. Most likely this will be USB or SD Card.

 Press Measure 1 OR Freq/Dist then More

 Then Radio Standard

 Then Import Radio Standards

 Then select the *.csv file using the ▲|▼ arrows or rotary knob and press

Enter.

 Custom Radio Standards can be removed from the FieldFox by selecting

Measure 1 then Radio Standard then Delete Radio Standard.

 Then select the *.csv file to delete using the ▲|▼ arrows or rotary knob and

press Enter.

NOTE To overwrite a custom standard that is already uploaded to the FieldFox, you

must first delete the *.csv file from the FieldFox, then re-upload the file that contains the standard. A predefined internal standard (such as GSM 450) can NOT be deleted from the FieldFox.

Channel Selection

After a Radio Standard has been selected, the frequency range can be changed by selecting channel numbers rather than frequency. Once enabled, the channel number is appended to the X-axis frequency range.

How to enable Channel selection

 Press Freq/Dist

 Then More

 Then Unit Freq Chan

How to change the Channel Number of the measurement

With Unit = Chan the FieldFox will NOT allow you to specify channels outside of the selected Radio Standard.

 Press Freq/Dist

 Then choose from the following:

o Center Channel Places the center frequency of the specified channel in the

middle of the X-axis.

o Start Channel Places the lowest frequency of the specified channel at the

beginning of the X-axis.

o Stop Channel Places the highest frequency of the specified channel at the

end of the X-axis.

o Freq Span Changes the span of frequencies while the center frequency

remains unchanged.

o Follow each of the above settings by entering a value using the numeric

keypad or the rotary knob.

SA (Spectrum Analyzer) Mode 79

o Use the ▲|▼ arrows to increment the channel number by an amount

specified by the Channel Step value (see below).

o Then press Enter.

Select either Uplink or Downlink Frequencies

Press Chan Direction to toggle between Uplink and Downlink. If either of these selections is not available, then the selected Radio Standard does not contain those frequencies.

Channel number X-axis annotation

 Dn indicates Downlink frequencies.

 Up (not shown) indicates Uplink frequencies

 (−) indicates that the lowest frequency in the channel (128) is at the left edge

of the screen.

 (+) indicates that the highest frequency in the channel (130) is at the right edge

of the screen.

 When Center Channel or Freq Span is specified, the X-axis shows the Center

Freq (Channel) and Frequency Span.

 When Start or Stop Channel is specified, the X-axis shows the Start Freq

(Channel) and Stop Freq (Channel).

Change Channel Step Size (Optional)

This setting allows you to use the ▲|▼ arrows to increment the channel number by the specified value.

 Press Channel Step

 Enter a step value using the numeric keypad, the ▲|▼ arrows, or the rotary

knob. Then press Enter .

Scale and Units

Adjust the Y-axis scale to see the relevant portions of the data trace.

The Y-axis is divided into 10 graticules. A Reference Level is shown on the screen as a solid horizontal bar that can be placed at any graticule.

When RF Attenuation set to Auto, the RF Attenuation is coupled to Reference Level.

How to set Scale

Press Scale / Amptd . Then choose from the following:

80 FieldFox User’s Guide

 Scale Type [current setting]

o Log Logarithmic scale (default setting). The Y-axis reference line represents

the specified absolute Reference Level in the current Unit selection. Y-axis graticules show dB below or above the reference line.

o Lin Linear scale. The Y-axis reference line represents the specified absolute

Reference Level in the current Unit selection. Y-axis graticules show percent of Reference Level (%) below or above the reference line.

 Manually set Scale, Reference Level, and Reference Position.

o Scale Manually adjust the scale per division to view specific areas of the

current trace. Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob. Then press Enter.

o Ref Level Manually set the value of the reference line. Enter a negative

value by pressing Run/Hold (+/-) either before or after typing a value. This can also change the RF Attenuation setting. See Attenuation Control – Auto.

o Ref Position Manually set the position of the reference line. Values must be

between 0 (TOP line) and 10 (BOTTOM line). Default position is zero (top).

o Press More, then Autoscale Automatically adjusts the Y-axis to comfortably

fit the Min and Max amplitude of the trace on the screen.

How to set Y-axis Units

The Unit setting appears for the reference line, marker readouts, and trigger level. All Unit choices are available in both Log and Linear Scale Types.

The UNIT setting survives Mode Preset, but NOT Preset.

 Press Scale / Amptd , then More, then Unit

 Then choose from the following:

o dBm (default setting), dBmV (dB milli Volts), dBuV (dB microVolts), W

(watts), V (volts), A (amps), dBmA (dB milliAmps), dBuA (dB microAmps).

Antenna correction units are available ONLY by loading or editing an Antenna file that contains the desired units setting. Learn more on page 84.

External Gain

When using an external amplifier or attenuator, the SA mode trace amplitude values can be offset to compensate for the effect of the external device. This effectively moves the reference plane of the SA measurement port out to just beyond the external device. For example, when using an external preamp with gain of +10 dB, enter this value for External Gain, and the data trace across the displayed frequency span will be adjusted down by 10 dB.

When RF Atten is set to Auto, you may see a change in the RF Attenuation value. This is an attempt to measure the signal at top of screen (the Reference Level) without overloading the SA first mixer.

How to set External Gain

 Press Scale/Amptd .

 Then More

SA (Spectrum Analyzer) Mode 81

WARNING

The FieldFox can be damaged with too much power.

RF Damage Level: +27 dBm

DC Damage Level: ±50 VDC

 Then External Gain

 Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob

(positive for gain; negative for loss). Values less than 5 dB must be typed using the numeric keypad. Then press Enter

ExtGain xx dB is shown at the top of the screen.

Attenuation Control

Both the RF Attenuation and Pre Amp functions control the power level into the SA.

When too much power is present at the RF Input port, ADC Over Range appears on the FieldFox screen. This does not necessarily mean that damage has occurred, but that the measurement is probably compressed.

When high power levels are present at the RF Input connector, internal attenuation can be switched in to keep the FieldFox receiver from compressing. At extremely high power levels, use external attenuation to protect the internal circuitry from being damaged.

The displayed power level is automatically adjusted for RF Attenuation. As the attenuation value changes, the displayed power level should NOT change.

How to set Attenuation

The default Attenuation setting is 10 dB. This value can be changed from 0 to 31 dB in 1 dB steps.

 Press Scale/Amptd .

 Then RF Atten Auto Man.

 Auto RF Attenuation is set by adjusting the Reference Level. As the Reference

Level is lowered, for example from –10 dB to –30 dB, the FieldFox assumes that you are looking at low-level signals. The RF Attenuation value is automatically lowered in 5 dB steps to allow low-level signals to be viewed. The RF Attenuation value is never automatically lowered below 5 dB.

 Man RF Attenuation is set manually. Enter a value using the numeric keypad,

the ▲|▼ arrows, or the rotary knob. Values less than 5 dB must be typed using the numeric keypad. Then press Enter

#Atten xx dB is shown at the top of the screen. (#) means manual setting.

Preamplifier Control (Opt 235)

When very low-level signals are analyzed, an internal preamplifier can be used to boost the signal level by approximately 22 dB. The gain of the preamp is NOT adjustable. The displayed signal level is automatically adjusted for the increase in system gain.

82 FieldFox User’s Guide

How to control the Preamp

By default, the preamp is OFF.

 Press Scale/Amptd .

 Then Preamp ON OFF The underlined setting is the current setting. When ON,

PA is shown to the left of the graticules on the display.

Check for Compressed Measurements

Compression occurs when too much power into an amplifier causes it to no longer amplify in a linear manner. When too much power goes into the FieldFox RF Input connector, the amplifiers in the SA receiver compress and signal power will not be displayed accurately. This can occur even if ADC Over Range is not displayed. Increase the RF Attenuation value to prevent the SA receiver from being compressed.

How to Check for a Compressed Measurement

 Using a marker at the signal peak, make note of the signal power level.

 Increase the RF Attenuation level by 5 dB.

o If the signal level does NOT change, then NO compression exists. This

indicates that the signal is in the linear region of the FieldFox receiver.

o If the signal level DOES increase, then the receiver was compressed. Set the

RF Attenuation value at the setting when further increases no longer result in an increase in the displayed power level.

Field Strength Measurements

To measure the strength of any signal transmitted through the air, an antenna must be connected to the FieldFox. The Field Strength feature allows you to enter the frequency response of the receiving antenna (the Antenna Factor) and associated cabling, and then have amplitude corrections automatically compensate the displayed trace for that response.

Field Strength Measurements

SA (Spectrum Analyzer) Mode 83

Trace 1 - Corrected trace with antenna factor. (Antenna = ON, Apply Corr = ON)

Trace 2 - (View) Uncorrected trace (Apply Corr = OFF)

Red Trace - Current correction factor. See below.

 Learn how to set Y-Axis Units on page 80.

 Use a Band Power marker to measure total power over a range of frequencies.

Learn how on page 158.

How to select correction for Field Strength measurements

The Antenna and Cable correction data survives a Mode Preset and Preset.

All Correction ON/OFF states survive a Mode Preset, but NOT a Preset.

 Press Scale/Amptd .

 Then More

 Then Corrections

 Then choose from the following:

o Apply Corrections ON OFF Turn ON and OFF correction for all settings

o Antenna ON OFF Turn ON and OFF Antenna correction.

o Edit/Save/Recall Antennas Recall or edit an Antenna Correction table. See

below.

o Cable ON OFF Turn ON and OFF Cable correction.

o Edit/Save/Recall Cables Recall or edit a Cable Correction table. See below.

o View Corrections ON OFF Turn ON and OFF Red Trace - Antenna/Cable

corrections.

Using the Antenna/Cable Editor

The Antenna Editor and the Cable Editor menus are very similar. Both tables include header information, and a Frequency/Value table.

FieldFox Antenna Editor

84 FieldFox User’s Guide

How to use the Antenna/Cable Editor

 Press New then Yes to clear all data from the existing Antenna or Cable table

and reset header information to default settings.

 Then Edit Antenna or Edit Cable to open the Antenna / Cable Editor.

 Then use the ▲|▼ arrows to select a field,

o To edit header information, press Edit then modify the selected field using

the FieldFox labeler.

o Description: Enter a description for the antenna or cable correction

table. This is NOT the filename used to save the file.

o Antenna Unit: Units in which the measurement will be displayed. Select

NONE (default setting) to select from standard SA Units on the Scale menu. Learn how on page 80.

o Choose from: dB μV/m - (dB micro Volts per meter), dB μA/m - (dB

micro Amps per meter), dBG (gauss), dBpT (tesla).

o Freq Interpolation: Set to LINear and can NOT be edited.

o To edit Frequency/Value pairs, enter numbers using the numeric keypad,

and a frequency suffix when necessary.

o For Cable Loss, positive values are interpreted as LOSS; negative values

are interpreted as GAIN which is used to describe an amplifier.

o For Antenna Factor, only positive values are valid. Antenna factor

describes the dB value needed to accurately display a far-field signal in terms that are in the units listed below. When the antenna has low gain, or low efficiency, the dB value to be added is larger. Learn more about Antenna Factor at:

http://tdkrfsolutions.com/DataPDFs/antenna_paper_part3.pdf

o When one Freq/Value pair is entered, that correction value is applied to the

entire displayed frequency span.

o When two or more Freq/Value pairs are entered, the data points between the

lowest and highest frequencies are corrected. Linear interpolation is applied between frequencies when necessary.

 Optionally choose from the following:

o Previous / Next Page Quickly scrolls through pages of Freq/Value data.

o Add Data Add a blank Freq/Value pair to the table,

o Delete/Clear then:

o Delete Line Remove the selected Freq/Value pair from the table.

o Clear All then Yes Remove all Freq/Value pairs from the table and resets

header information to default settings.

When the table edits are complete

 Press Done to close the Antenna/Cable Editor.

SA (Spectrum Analyzer) Mode 85

 Press Save Antenna or Save Cable to saves your changes to the specified

Storage Device. Enter a filename using the FieldFox labeler (learn more on page 164). Learn more about Antenna and Cable files below.

 Press Recall Antenna or Recall Cable to load an Antenna or Cable file from

the specified Storage Device.

 Storage Device Changes the device used to save or recall files. Choose from

Internal (default setting), USB (must be connected) or SD card. This is a different setting from the Save/Recall Storage Device setting.

About Antenna and Cable files

 Cable files are saved and recalled from the Cables folder.

 Antenna files are saved and recalled from the Antenna folder.

 If the folder does not already exist on a USB or SD card, it is created

automatically before storing the file.

 All SA mode Antenna and Cable files are saved and recalled as *.csv files,

which allows them to also be read by spreadsheet programs.

 The FieldFox can also read *.ANT (Antenna) files that were created from older

Agilent Spectrum Analyzers.

 Data Link does NOT support the SA Mode cable or antenna (*.csv or *.ANT)

files. Learn more about Data Link software at:

http://na.tm.agilent.com/fieldfox/datalink_info.html

How to create a Cable file from an S21 (NA mode) measurement

1. Measure the S21 of a cable. Learn how in NA mode on page 39.

2. Use Manage Folders to change the active folder to CABLES. Learn how to manage folders on page 169.

3. Save the measurement as a *.csv file. Learn how on page 166.

4. Recall the *.csv file for correction.

Tune & Listen (AM/FM)

The Tune & Listen feature can be used to identify an interfering AM or FM signal.

The demodulated AM or FM signal can be heard through the internal speaker or through headphones using the 3.5 mm jack located on the FieldFox side panel.

The Tune & Listen tuner is separate from the SA display. This allows you to listen to one frequency while displaying a different range of frequencies. The Tune & Listen measurement alternates between normal SA sweeps for the display and performing audio demodulation at the Tune Frequency. See the Listen Time setting for more information.

86 FieldFox User’s Guide

Tune & Listen ON with Tune Frequency indicated by a vertical bar (highlighted).

How to select Tune & Listen

 Press Measure 1

 Then Tune & Listen

 Then choose a demodulation type. Select a setting based on the type of

interfering signal you suspect is being broadcast.

o None Turns Tune & Listen OFF

o AM Amplitude Modulation

o FM Narrow Frequency Modulation; Narrow bandwidth. Choose when

interfering transmission consist of voice or data.

o FM Wide Frequency Modulation; Wide bandwidth. Choose for high quality

music transmissions of FM broadcast radio.

Tune Frequency

The Tune & Listen tuner is separate from the SA display. This allows you to listen to one frequency while displaying a different range of frequencies.

Set the Tune Frequency using one of three methods:

1. Selecting Preset, Mode Preset, or Meas Preset sets Tune Frequency to 3.0 GHz.

2. Specify Tune Frequency:

 Press Meas Setup 4

 Then Tune Freq

 Enter a value using the numeric keypad, ▲|▼ arrows, or the rotary knob.

Then select a multiplier key. Learn about multiplier abbreviations on page 19.

 3. Using Mkr->Tune Freq

 Create a normal marker at the frequency of interest. Learn how on page 148.

 Press Mkr->/Tools

SA (Spectrum Analyzer) Mode 87

 Then Mkr->Tune Freq to change the Tune Frequency to that of the marker.

Tip To improve sound quality, try increasing power by reducing the Attenuation

setting and, if available, turn ON the Preamplifier. Learn how on page 81.

Listen Time

While Tune & Listen is actively demodulating a signal, the SA does not sweep and update the display. Listen Time sets the amount of time that the FieldFox demodulates, then stops to perform a single sweep and update the display, then again demodulates.

To select Listen Time:

 Press Meas Setup 4

 Then Listen Time

 Enter a value using the numeric keypad, ▲|▼ arrows, or the rotary knob.

Then select a multiplier key. Learn about multiplier abbreviations on page 19.

Volume Control

 To increase or decrease the Volume of the demodulated signal:

 Press Meas Setup 4

 Then Volume

 Enter a value in percent between 0 and 100 (loudest) using the numeric

keypad, ▲|▼ arrows, or the rotary knob.

 Volume can also be changed and easily muted from the System menu. Learn

Independent Source/Tracking Generator

This feature may require an option. For a comprehensive list, view the FieldFox Configuration Guide at: http://cp.literature.agilent.com/litweb/pdf/5990-

9836EN.pdf

A tracking generator, a popular option with Spectrum Analyzers, is a source which always tracks the SA receiver.

Like a traditional tracking generator, the Independent Source feature can set the internal FieldFox source to track the SA receiver frequency range. It can also set the internal source to a CW frequency that is independent of the SA frequency.

Independent Source can be enabled ONLY when the FieldFox is in SA mode.

To view the internal source, you must connect a cable or device between the RF Output connector and the RF Input connector.

How to make Independent Source Settings

 Press Measure 1

88 FieldFox User’s Guide

 Then Source

 Source Enable ON OFF

o ON Turns ON the internal source.

o OFF Turns OFF the internal source.

 Source Mode Choose from the following:

o Tracking The internal source sweeps simultaneously (tracks) with the SA

receiver over the displayed frequency range, emulating NA mode measurements. Src is annotated on the screen.

o CW The source is set to a CW frequency independent from the SA setting.

Srcw is annotated on the screen.

o Coupled CW The source is set to a CW frequency, but that frequency

“tracks” the SA receiver Center Frequency setting. Therefore, the signal always appears at center of the display. Srcp is annotated on the screen.

 Normalize ON OFF With Source Enable ON and Source Mode = Tracking,

Normalize ON stores the current measurement trace into Trace 4 in View state as a reference trace. All subsequent trace measurements subtract this Trace 4 reference trace, and therefore become relative to it. SrcN is annotated on the screen. Normalize is automatically turned OFF when the frequency range or Resolution is changed. Learn more about Trace Display States on page 99.

 Source Power Sets the source power level. Choose from:

o Leveled Enter a value from -45 dBm to 0 dBm using the numeric keypad,

▲|▼ arrows, or the rotary knob. The source power is reasonably flat across

the frequency span.

o MAX The power level is set to the maximum achievable power level at each

frequency. This results in the power level NOT being flat across the frequency span.

 Source CW Freq Sets the CW frequency that is used when Source Mode is set

to CW.

NOTE By default, the source output will turn off momentarily at the end of each SA

sweep and every thirty seconds for InstAlign.

To cause the source to stay ON at the end of each sweep, turn battery saver OFF. (Learn about Battery Saver on page 177.)

 Press System 7

 Then Preferences

 Then Battery Saver OFF

To suspend InstAlign: (Learn about InstAlign on page 100.)

 Press Cal 5

 Then Amptd Alignment OFF

SA (Spectrum Analyzer) Mode 89

Resolution Bandwidth (Res BW)

In SA Mode, the Res BW provides the ability to resolve, or see closely spaced signals. The narrower (lower) the Res BW, the better the spectrum analyzer can resolve signals. In addition, as the Res BW is narrowed, less noise is measured by the spectrum analyzer ADC and the noise floor on the display lowers as a result. This allows low level signals to be seen and measured. However, as the Res BW is narrowed, the sweep speed becomes slower.

How to set Res BW

 Press BW 2.

 Then Res BW

 Then choose from the following:

o Auto Res BW is coupled to the frequency span. As the frequency span is

narrowed, the Res BW is also narrowed providing increased ability to resolve signals. To change this setting from Man to Auto, press Res BW twice.

o Man Enter a Res BW value using the numeric keypad, the ▲|▼ arrows, or

the rotary knob. Then press a multiplier if necessary or press Enter .

The current Res BW setting is shown at the bottom of the screen.

#Res BW x.xx XHz ( # ) means manual setting.

This setting could impact the accuracy of the measurement. See Specifications on page 194.

NOTE The Res BW setting also affects the Sweep Type setting. Learn how on page 91

Video Bandwidth (Video BW)

Video BW is a smoothing operation that is performed after measurement data is acquired. The trace data is effectively smoothed so that the average power level of the displayed noise is the same, but the peaks and valleys of adjacent data points are smoothed together. More smoothing occurs as the Video BW is set lower. However, as the Video BW is narrowed, the sweep speed becomes slower.

How to set VBW

 Press BW 2.

 Then Video BW

 Then choose from the following:.

o Auto Couples Video BW to the ResBW in a 1-to-1 ratio.

o Man Enter a Video BW value using the numeric keypad, the ▲|▼ arrows,

or the rotary knob. Then press a multiplier if necessary or press Enter.

NOTE To change this setting from Man to Auto, press Video BW twice.

The current Video BW setting is shown at the bottom of the screen.

# VBW x.xx XHz ( # ) means manual setting.

When the Res BW/Video BW ratio exceeds 10,000, a Meas UNCAL warning may appear to indicate that the Video BW filter has reached the maximum capacity for averaging.

90 FieldFox User’s Guide

In Zero Span, the maximum Res BW/ Video BW ratio is 100.

Sweep Type

In SA mode, the FieldFox uses two sweep types to process inputs signals. The sweep type that is currently being used (FFT or Step) is displayed in the lowerleft corner of the FieldFox screen.

For a more comprehensive tutorial, see Spectrum Analysis Basics (App Note 150) at http://cp.literature.agilent.com/litweb/pdf/5952-0292.pdf

How to set Sweep Type

 Press BW 2.

 Then Advanced

 Then Sweep Type

 Then choose from the following:

o Auto The FieldFox selects the most efficient sweep type based on the Res

BW. When Res BW is set to 200 kHz and below, FFT sweep type is selected. Above 200 kHz, Step sweep type is being performed.

o FFT The FieldFox uses FFT sweep type regardless of the Res BW.

o Step The FieldFox uses Step sweep type regardless of the Res BW. This is

useful for capturing impulsive noise that may be generated from nearby electrical equipment.

IF Output

The FieldFox IF (intermediate frequency) can be output for external signal processing. The signal is available from the IF Out connector on the FieldFox right-side panel. See the connector on page 17.

The IF Out signal, centered at approximately 33.75 MHz, is simply a downconverted version of the RF Input signal that is present at the tuned frequency.

While outputting an IF signal, the FieldFox stops performing the InstAlign process. Therefore, the amplitude of traces on the FieldFox screen is NOT accurate and Meas UNCAL appears on the screen to indicate this. Learn more about InstAlign on page 100.

Learn more about the IF Output frequencies and bandwidths in the

Supplemental Online Help: http://na.tm.agilent.com/fieldfox/help/FieldFox.htm

How to select IF Output

The IF Output signal is useful only in Zero Span. Learn more about Zero Span on page 93.

At least one sweep must be made in order to tune the FieldFox.

 Press BW 2.

 Then Advanced

 Then IF Output Use

 Then choose from the following:

o OFF No output from the IF Out connector.

SA (Spectrum Analyzer) Mode 91

o Narrow The IF output signal has approximately 5 MHz bandwidth.

o Wide The IF output signal has approximately 25 MHz bandwidth.

Sweep Acquisition

When set to Auto, Sweep Acquisition is set to the minimum value required with the current settings in order to achieve amplitude accuracy when measuring CW signals yielding the fastest sweep update rate.

However, you can adjust this setting in order to increase the probability of intercepting and viewing pulsed RF signals.

For example, with SwpAcquisition set to Auto a pulsed GSM signal is NOT visible on the FieldFox screen, as shown in a blue trace in the following image.

However, while watching the trace, increase the SwpAcquisition value until the pulse spectrum rises out of the noise and reaches its maximum level. Increasing the SwpAcquisition value beyond this point only slows the update rate (increases the actual Sweep time readout) but does not improve measurement quality.

A GSM signal in a framed data format; timeslot zero ON; all others OFF;

PRF = 218Hz, Duty Cycle = 12.5%. The pulsed signal becomes visible on every sweep

update with SwpAcquisition = 50.

How to set Sweep Acquisition Parameter

 Press Sweep 3 .

 Then SwpAcquistion Auto Man.

 Then choose from the following:

o Auto Sweep is set to the fastest sweep possible with the current settings.

o Man Enter a relative acquisition value between 1 and 5000, where:

o 1 = Fastest sweep possible

o 5,000 = Slowest sweep possible

92 FieldFox User’s Guide

o # is shown in front of the actual sweep time to indicate a manual setting.

Some Detector and Video Bandwidth settings will raise the Auto Sweep Acquisition value greater than 1. In these cases, manually setting Sweep Acquisition lower than the Auto value may have NO effect.

NOTE Measurement speed specifications do NOT apply in Temperature Control Mode.

Learn more on page 13.

Zero Span Measurements

When setting the frequency span to Zero, there is NO spectrum of frequencies to display, so the X-axis units becomes Time. The SA becomes like a tunable oscilloscope, with the center frequency being the frequency of interest. This capability is useful for analyzing modulation characteristics, such as pulsed measurements.

GSM signal, framed data format, timeslot 0 and 3 on. Sweep Time is set to approximately the frame interval. Press Single several times until the waveform section of interest is viewable and stable. Then markers can be used to measure the timeslot width and interval as shown.

How to set Zero Span

 Set Center to the frequency of interest

o then set Span to 0 Hz

o or select Zero/Last Span. Each key press toggles the frequency span

between 0 Hz and the last specified frequency span.

How to change Sweep Time in Zero Span.

 Press Sweep 3

 Then SweepTime

 Enter a value using the numeric keypad.

SA (Spectrum Analyzer) Mode 93

 Then select a multiplier key. Learn about multiplier abbreviations on page 19.

Previous FieldFox versions limited the sweep time / ResBW settings. This restriction is no longer necessary with release A.06.25.

Triggering

External, Video, and RF Burst triggering allows you to initiate an SA mode sweep using an external event such as a signal burst.

All three trigger types can be used in either Zero Span (time domain) or FFT frequency sweeps. Learn more about Zero Span on page 93. Learn more about FFT on page 91 .

FFT Gating is available for non-zero span measurements. Learn more about FFT Gating on page 97.

Trigger Type

 Press Sweep 3

 Then Trigger Settings

 Then Trig Type

 Then choose from the following:

o Free Run Triggering is provided by the FieldFox internal circuitry. A new

sweep begins when the previous sweep ends.

o External A sweep is triggered on an external TTL signal at the Ref In/Trig

In connector on the FieldFox top panel. Choose to trigger on the rising slope

at about 1.7 V or on the falling slope at about 1.0 V using the Trigger Slope setting (below).

The following two selections are similar in that they both a trigger a sweep from a signal at the SA RF Input connector. Experiment with both selections to find the best trigger type for your application.

o Video A sweep is initiated when the displayed amplitude of an incoming

signal crosses the settable Trigger Level. This selection can detect lowamplitude signals, but also has been filtered considerably and may not be a true representation of the incoming signal.

o RF Burst A sweep is initiated when the signal at the third IF (analog) stage

crosses the settable Trigger Level. This selection offers a wider bandwidth and may be a better representation of the incoming signal than Video trigger. However, RF Burst is not as sensitive to triggering on low-level signals.

Trigger Slope

Trigger Slope determines which edge of an External, Video, or RF Burst trigger signal initiates a sweep.

 Press Sweep 3

 Then Trigger Settings

 Then Trig Slope

 Then choose from the following:

o Pos Sweep is triggered by the rising (positive) edge of signal.

94 FieldFox User’s Guide

o Neg Sweep is triggered by the falling (negative) edge of signal.

Trigger Delay

After a valid trigger signal is received, the sweep begins after the specified Trigger Delay time.

To see the rising edge of a repetitive signal which is triggered on that edge, enter a negative trigger delay value (also known as pre-trigger). Adjust the sweep time to include the pre-trigger time.

 In Zero span, you can use Trigger Position as an easy way to set Trigger Delay

by positioning the trigger event on the FieldFox screen.

 Press Sweep 3

 Then Trigger Settings

 Then Trig Delay

 Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob.

 Then select a multiplier key or press Enter. Learn about multiplier

abbreviations on page 19.

Trigger Level

Used with Video and RF Burst triggering, a sweep is initiated when an incoming signal crosses this level. The units depend on the Units setting. Learn more on page 80.

Video Trigger Level is a zero span signal level comparison. Therefore, the sweep will trigger close to the displayed level in zero span measurements. In non-zero span measurements, processing can cause broadband signal energy to display at lower power levels than the originating time domain signal. Therefore, you may need to set the trigger level higher than the displayed level.

RF Burst Trigger Level uses an alignment process which is performed in the background to set the detected signal level accuracy. Learn more about the alignment on page 101.

 Press Sweep 3

 Then Trigger Settings

 Then Trig Level

 Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob.

 Then select a multiplier key or press Enter. Learn about multiplier

abbreviations on page 19.

Auto Trigger Time

While waiting for a valid trigger signal, Wait is annotated in the top left corner of the FieldFox screen.

If a valid trigger signal is not received before the specified Auto Trig Time, a sweep will occur automatically.

Enter 0 to set Auto Trigger OFF. When Auto Trigger is OFF, the FieldFox does NOT sweep unless a valid trigger signal is received.

 Press Sweep 3

 Then Trigger Settings

SA (Spectrum Analyzer) Mode 95

 Then AutoTrig Time [current setting]

 Enter an Auto Trig Time using the numeric keypad.

 Then select a multiplier key. Learn about multiplier abbreviations on page 19.

Trigger Position

Available ONLY in zero span measurements, this setting is an easy way to automatically set the Trigger Delay by positioning the trigger event (also known as T zero) at any graticule along the X-axis. With T zero in the center of the screen, you can zoom in and out by increasing or decreasing the sweep time. Using the Trigger Position and Sweep Time settings is a quick and efficient way to examine artifacts of a pulse, much easier than trying to set the Trigger Delay manually.

When Trigger Position is set to Manual, the Trigger Delay softkey is not available. The amount of Trigger Delay that is being used is displayed on the softkey. The Trigger Position is annotated on the screen. Learn how in the following section.

 Press Sweep 3

 Then Trigger Settings

 Then Trig Position

o Auto: The position of T zero is set by the trigger delay.

o Manual: Select, then enter a position value from 0 to 10 using the numeric

keypad, the ▲|▼ arrows, or the rotary knob.

o 0: T zero occurs at the left graticule.

o 5: T zero occurs at the center of the screen.

o 10: T zero occurs at the far right graticule.

o Then press Enter.

Trigger Settings Annotation

Trigger settings are annotated on the FieldFox screen as highlighted in red in the following image:

 Square: Trig Type (VidT), AutoTrigger (a), Pos Slope (/), Neg Delay (delay-)

96 FieldFox User’s Guide

 Horizontal arrow: Trig Level (green horizontal graticule at -20 dBm)

 Vertical arrow: Trig Position (green arrows at 2nd vertical graticule)

FFT Gating (Opt 238)

Time-gated spectrum analysis allows you to obtain spectral information about signals occupying the same part of the frequency spectrum that are separated in the time domain. Using an external trigger signal to coordinate the separation of these signals, you can perform the following operations:

 Measure any one of several signals separated in time; for example, you can

separate the spectra of two radios time-sharing a single frequency.

 Measure the spectrum of a signal in one time slot of a TDMA system.

 Exclude the spectrum of interfering signals, such as periodic pulse edge

transients that exist for only a limited time.

FFT Gating is a simple, efficient way to set the proper amount of trigger delay and capture time so that signal artifacts of a repeating waveform or pulse can be examined in the frequency domain. Learn more about trigger settings on page 94.

For best results, Auto Trigger should be used with this feature to ensure that the sweep does not wait indefinitely for a trigger. Set Auto Trigger to a time that is longer than the expected periodic rate of the signal. This is especially important when using RF Burst or Video triggering in wider spans, because the signal providing those triggers has limited bandwidth. Learn more about Auto trigger on page 95.

For more conceptual information on this topic, please refer to Spectrum Analysis Basics (App Note 150) at http://cp.literature.agilent.com/litweb/pdf/5952-

0292.pdf, pages 38-42.

How to set FFT Gating

 Create a non-zero span measurement. Wider frequency spans take more time

to acquire.

 Press Sweep 3

 Then Trigger Settings

 Then FFT Gating Setup

 Then choose from the following:

o Gate View OFF ON When ON, a separate zero span measurement is

displayed below the non-zero span window. The gate view measurement helps to configure the gate width and delay by revealing (with green markers) the location of the gate relative to the trigger event. The zero span measurement is tuned to the center frequency of the non-zero span measurement with about 5 MHz of bandwidth. The Y-axis scale is the same for both windows.

o Gate View Time Set the X-axis span for the non-zero span window. Enter a

value using the numeric keypad, the ▲|▼ arrows, or the rotary knob. This value is annotated as Swp (nn) below the window.

SA (Spectrum Analyzer) Mode 97

o FFT Gating OFF ON When ON, the trigger type, gate width, and delay are

applied to the non-zero span measurement. The Res BW is set to a value that is inversely proportional to the gate width.

o Gate Width Set the width of the gating area within the non-zero span

window. The gating area is indicated by two vertical green lines. Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob.

o Gate Delay Effectively moves the gating area left (negative delay) or right

(positive delay) relative to the trigger event. Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob.

When you have properly setup the Gate Trigger, Width, and Delay using the Gate View measurement, you can turn Gate View OFF to return to the full screen nonzero span measurement with FFT Gating ON, the RBW set, and the Trigger settings active.

Single / Continuous / Restart

NOTE The following behavior is unique to SA Mode.

This setting determines whether the FieldFox measures continuously or only once each time the Single or Run / Hold +/- button is pressed. Use Hold / Single or to conserve battery power or to allow you to save or analyze a specific trace.

How to set Single or Continuous

 Press Sweep 3 .

 Then choose one of the following:

o Continuous

o ON Causes the SA to make continuous sweeps. This is the typical setting

for making measurements. Each Run / Hold +/- press causes the SA to toggle between continuous sweep and Hold.

o OFF Causes the SA to Hold. Each Run / Hold +/- or Single press causes

the SA to make ONE sweep, then Hold. The Hold annotation changes to an arrow --> while the sweep occurs.

o Single Automatically sets Continuous OFF and causes the SA to make ONE

sweep, then Hold.

o Restart Resets the Average counter to 1. When in Hold, causes the SA to

make ONE sweep, then Hold. The Average counter has is used with MaxHold and MinHold Trace States. Learn more on page 100.

Points

Points is the number of measurements that are displayed along the X-axis. The higher number of data points, the better the ability to resolve closely spaced signals and the slower the sweep speed.

How to set number of points

 Press Sweep 3

 Then Points [current setting]

98 FieldFox User’s Guide

 Then choose from: 101 | 201 | 401 | 601 | 801 | 1001

Trace Display States

In SA Mode you can display up to four of the following types of trace states. All SA settings are applied to all displayed traces.

A color-coded legend for displayed traces is visible in the left pane of the SA mode screen:

W = Clear/Write; M = MaxHold; m = MinHold; A = Average; V = View

How to display Trace States

 Press Trace 6 .

 Then Trace 1,2,3,4 repeatedly to select a trace number to display. Traces are

displayed in the following colors:

o Trace 1 – Yellow Trace 2 – Blue

o Trace 3 – Orange Trace 4 – Red

 Then State [current setting] .

 Then choose from the following Trace States:

o Clr /Wr (Clear/Write) Displays the actual measured data for each sweep.

o MaxHold Displays the maximum response of the input signal at each data

point over multiple sweeps. See also Average Count on page 100.

o MinHold Displays the minimum response of the input signal at each data

point over multiple sweeps. See also Average Count on page 100.

o Average Each data point is averaged over multiple sweeps as set by the

Average Count setting. Learn more in following Average Type section.

o View Displays and then holds the last complete measurement trace on the

screen. This is similar to storing a trace in memory.

o Blank Displays no trace.

 Press Default All to return all traces to their default settings: Trace 1

(Clear/Write); all other traces (Blank).

NOTE Trace 4 data WILL be overwritten by the FieldFox when using the Independent

Source Normalize feature (page 86) or using Field Strength antenna or cable corrections (page 83).

Average Type

In SA Mode, there are four different processes in which Averaging is performed:

 Average Traces – Learn more on page 99.

 Detection Method Averaging – Learn more on page 101.

 Noise Marker Averaging - Learn more on page 103.

 Video BW filtering (for non-Zero Span measurements) - Learn more on page

90.

SA (Spectrum Analyzer) Mode 99

There are two types of mathematical averaging that can be performed. Select ONE of these types and it is used for all of the above averaging processes.

How to set Average Type

 Press Meas Setup 4

 Then choose from the following:

o Auto - The FieldFox chooses the most appropriate type of averaging for the

current settings. When Detection Method is set to Average, a Noise Marker is present, or a Channel measurement is active, then Power Average is ALWAYS selected. Otherwise, Log Average is selected.

o Log Averaging – Best for displaying Trace Averaging. LgAv is shown on the

left side of the FieldFox screen when selected.

o Power (Linear) Averaging – Best for measuring true power levels. Used in

Detection Average and Noise Marker Average. Mathematically, trace noise is

2.5 dB higher than when using Log Average. PAvg is shown on the left side of the FieldFox screen when selected.

Average Count

The Average Count setting is used mainly with the Average Trace State described above. In this Trace State, the Average Count setting determines the number of sweeps to average. The higher the average count, the greater the amount of noise reduction.

When Trace (display) State is set to Average, MaxHold, or MinHold, the average counter is shown in the left edge of the screen below the Average Type.

For all three of these Trace States, when Sweep 3 Continuous is set to OFF, press Restart to reset the sweep count to 1, perform <n> sweeps, then return to

Hold.

How to set Average Count

 Press Meas Setup 4

 Then Average Count

 Enter a value from 1 to 10,000 using the numeric keypad, the ▲|▼ arrows, or

the rotary knob.

 Press Enter

InstAlign Amplitude Alignment

SA mode uses a proprietary amplitude alignment algorithm to make extremely accurate amplitude measurements over the full frequency range of the FieldFox.

When enabled (by default) the FieldFox performs an alignment process using the internal RF source. Although some sweeps are delayed, measurement results are never disturbed.

If the Independent Source is enabled for your measurement, it will be borrowed to perform the alignment. Again, the measurement results are not disturbed. Learn about the Independent Source on page 88.

The alignment process can be disabled. You may want to do this, for example, if you are analyzing the amplitude stability of a signal.

100 FieldFox User’s Guide

Agilent Technologies N9917A, N9914A, N9918A, N9925A, N9926A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

A.07.00 Firmware Release Updates

Overview

Models and Options

Models

Accessories

FieldFox Manuals, Software, and Supplemental Help

Conventions that are used in the Manual

Safety Notes

Preparing for Initial Use of Your New FieldFox

Check the Shipment

Meeting Power Requirements for the AC/DC Adapter

Install the Lithium-Ion Battery

Battery Usage

FieldFox ON/OFF Settings

FieldFox High-Temperature Protection

Temperature Control Mode

High-Temp Shutdown

Avoid Overpowering the FieldFox

Take the FieldFox Tour

Front Panel

Top Panel

Right Side Panel

Left Side Panel

Screen Tour

How to Enter Numeric Values

Multiplier Abbreviations

CAT (Cable and Antenna Test) Mode

CAT Mode Settings

Measurement Selection

Coupled Frequency

Quick Settings Table

Frequency Range

Scale Settings

Averaging

Single or Continuous Measure

Resolution (Number of Data Points)

Sweep Time

Output Power

Interference Rejection

Return Loss Measurements

1-Port Cable Loss Measurements

How to make a 1-port Cable Loss Measurement

2-Port Insertion Loss Measurements

DTF (Distance to Fault) Measurements

How to make DTF Measurements

DTF Measurement Settings

DTF Settings Table

DTF Measurement (Format)

DTF Start and Stop Distance

Frequency Mode

Coupled Frequency

Cable (Correction) Specifications

Window Settings

DTF Units

Calculated DTF values

About Alias Faults

NA (Network Analyzer) Mode

NA Mode Settings

About S-parameters

Receiver Measurements

Multi-Trace Configurations

Quick Settings

Format

Frequency Range

Scale Settings

Electrical Delay

Phase Offset

Averaging

IF Bandwidth

Smoothing

Single or Continuous Measure

Resolution (Number of Data Points)

Sweep Time

Triggering

Output Power

System Impedance (Z0)