Anritsu 681XXC User Manual

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SERIES 681XXC

SYNTHESIZED SIGNAL GENERATOR

OPERATION MANUAL

490 JARVIS DRIVE MORGAN HILL, CA 95037-2809

P/N: 10370-10333

REVISION: B

PRINTED: APRIL 2001

WARRANTY

The Anritsu product(s) listed on the title page is (are) warranted against defects in materials and workmanship for one year from the date of shipment.

Anritsu’s obligation covers repairing or replacing products which prove to be defective during the warranty period. Buyers shall prepay transportation charges for equipment returned toAnritsu for warranty repairs. Obligation is limited to the original purchaser. Anritsu is not liable for conse quential damages.

LIMITATION OF WARRANTY

The foregoing warranty does not apply to Anritsu connectors that have failed due to normal wear. Also, the warranty does not apply to defects resultingfrom improper or inadequate maintenance by the Buyer, unauthorized modification or misuse, or operation outside of the environmental specifications of theproduct. No other warranty isexpressed or implied,and the remediesprovided herein are the Buyer’s sole and exclusive remedies.

TRADEMARK ACKNOWLEDGEMENTS

Adobe Acrobat is a registered trademark of Adobe Systems Incorporated.

NOTICE

Anritsu Company has prepared this manual for use by Anritsu Company personnel and customers as a guide for the proper installation, operation, and maintenance of Anritsu Company equipment and computor programs. The drawings, specifications, and information contained herein are the property of Anritsu Company, and any unauthorized use or disclosure of these drawings, specifica tions, and informationis prohibited; they shallnot be reproduced,copied, or used inwhole or inpart as the basis for manufacture or sale of the equipment or software programs without the prior writt ten consent of Anritsu Company.

Safety Symbols

To prevent the risk of personal injury or loss related to equipment malfunction, Anritsu Company uses the following symbols to indicate safety-related information. For your own safety, please read the information carefully BEFORE operating the equipment.

WARNING WARNING indicates a hazard. It calls attention to a procedure that

could result in personal injury or loss of life if not performed properly. Do not proceed beyond a WARNING notice until the indicated condi tions are fully understood and met.

CAUTION CAUTION indicates a hazard. It calls attention to a procedure which,

if not performed properly, could result in damage to or destruction of a component of the instrument. Do not proceed beyond a CAUTION note until the indicated conditions are fully understood and met.

The instrument is marked with this symbol to indicate that it is necessary for the user to refer to the instructions in the operation manual.

Indicates ground.

Indicates heavy weight equipment.

681XXC OM Safety-1

For Safety

WARNING

When supplying power to this equipment, always use a three-wire power cable connected to a three-wire power line outlet. If power is supplied without grounding the equip ment in this manner, there is a risk of receiving a severe or fatal electric shock.

WARNING

Before changing the fuse, always remove the power cord from the power outlet. There is the risk of receiving a fatal electric shock if the fuse is replaced with the power cord connected.

Always use a new fuse of the type and rating specified by the fuse markings on the rear panel of the instrument.

WARNING

There are no operator serviceable components inside. Refer servicing of the instrument to qualified service technicians.

To prevent the risk of electrical shock or damage to precision components, do not remove the equipment covers.

WARNING

Use two or more people to lift and move this equipment, or use an equipment cart. There is a risk of back injury, if this equipment is lifted by one person.

WARNING

If the equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.

Safety-2 681XXC OM

Chapter 1 General Information

1-1 SCOPE OF MANUAL.................1-3

1-2 INTRODUCTION ...................1-3

1-3 DESCRIPTION ....................1-3

1-4 IDENTIFICATION NUMBER ............1-5

1-5 ELECTRONIC MANUAL...............1-5

1-6 RELATED MANUALS ................1-5

GPIB Programming Manual ...........1-5

SCPI Programming Manual ...........1-5

Maintenance Manual ..............1-6

1-7 OPTIONS .......................1-6

1-8 PERFORMANCE SPECIFICATIONS ........1-7

1-9 RECOMMENDED TEST EQUIPMENT .......1-8

Chapter 2 Installation

2-1 INTRODUCTION ...................2-3

2-2 INITIAL INSPECTION ................2-3

2-3 PREPARATION FOR USE ..............2-4

Power Requirements...............2-4

Line Voltage Selection ..............2-4

Power Connection ................2-4

Standby Operation................2-5

Warmup Time ..................2-6

Operating Environment .............2-6

2-4 GPIB SETUP AND INTERCONNECTION .....2-7

Interface Connector ...............2-7

Cable Length Restrictions ............2-7

GPIB Interconnection ..............2-7

Setting the GPIB Address ............2-7

Selecting the Line Terminator ..........2-9

Selecting the Interface Language.........2-9

2-5 RACK MOUNTING KIT INSTALLATION .....2-10

Preliminary ..................2-10

Procedure ...................2-10

681XXC OM i

Table of Contents (Continued)

2-6 PREPARATION FOR STORAGE/SHIPMENT . . . 2-13

Preparation for Storage.............2-13

Preparation for Shipment............2-13

Chapter 3 Local (Front Panel) Operation

3-1 INTRODUCTION ...................3-5

3-2 FRONT PANEL LAYOUT...............3-6

Line Key ....................3-6

Data Display Area ................3-6

Data Entry Area.................3-7

RF Output Control Key .............3-7

Connectors ...................3-7

3-3 DATA DISPLAY AREA ................3-8

Menu Display Format ..............3-9

Menu Keys ...................3-10

3-4 DATA ENTRY AREA.................3-12

3-5 INSTRUMENT START-UP .............3-14

Powering Up the 681XXC............3-14

Start-Up Display ................3-14

Standby Operation ...............3-14

Self-Testing the 681XXC ............3-15

Resetting to Default Parameters ........3-15

3-10 POWER LEVEL SWEEP OPERATION.......3-53

Selecting CW Power Sweep Mode ........3-53

Setting CW Power Sweep Step Size and Dwell Time3-54

Selecting a CW Power Sweep Trigger ......3-55

Selecting a Power Level Sweep Range......3-56

Selecting a Sweep Frequency/Step Power Mode . 3-58

Setting Power Level Step Size .........3-59

3-11 LEVELING OPERATIONS .............3-60

Selecting a Leveling Mode ...........3-60

Attenuator Decoupling .............3-64

ALC Power Slope................3-65

User Cal (User Level Flatness Correction) . . . 3-67

3-12 SIGNAL MODULATION ..............3-73

Amplitude Modulation Operating Modes ....3-73

Providing Amplitude Modulation ........3-73

ii 681XXC OM

Table of Contents (Continued)

Frequency Modulation Operating Modes ....3-74

Providing Frequency Modulation ........3-75

Square Wave Modulation Operating Modes . . . 3-77

Providing Square Wave Modulation .......3-77

3-13 SYSTEM CONFIGURATION ............3-80

Configuring the Front Panel ..........3-81

Configuring the Rear Panel...........3-82

Configuring the RF ...............3-83

Configuring the GPIB .............3-85

Setting Increment Sizes ............3-88

3-14 SAVING/RECALLING INSTRUMENT SETUPS . 3-89

Saving Setups .................3-89

Recalling Setups ................3-89

Erasing Stored Setups .............3-90

3-15 SECURE OPERATION ...............3-91

3-16 REFERENCE OSCILLATOR CALIBRATION . . . 3-92

Chapter 4 Local Operation–Menu Maps

4-1 INTRODUCTION ...................4-3

4-2 MENU MAP DESCRIPTION .............4-3

Chapter 5 Operation Verification

5-1 INTRODUCTION ...................5-3

5-2 TEST EQUIPMENT..................5-3

5-3 TEST RECORDS ...................5-3

5-4 INITIAL 681XXC CHECKOUT............5-4

Power Up ....................5-4

Self Test.....................5-4

Resetting the 681XXC ..............5-4

Warmup Time ..................5-4

5-5 CW FREQUENCY ACCURACY TEST........5-5

Test Setup....................5-5

Test Procedure..................5-6

5-6 POWER LEVEL ACCURACY AND FLATNESS

TESTS ........................5-13

Test Setup ...................5-13

681XXC OM iii

Table of Contents (Continued)

Power Level Accuracy Test Procedure ......5-14

Power Level Flatness Test Procedure ......5-15

Chapter 6 Operator Maintenance

6-1 INTRODUCTION ...................6-3

6-2 ERROR AND WARNING/STATUS MESSAGES. . . 6-3

Self-Test Error Messages.............6-3

Normal Operation Error and Warning/ Status

Messages ....................6-8

6-3 TROUBLESHOOTING ...............6-10

6-4 ROUTINE MAINTENANCE ............6-13

Cleaning the Fan Filter.............6-13

Cleaning the Data Display ...........6-13

Replacing the Line Fuse ............6-14

Chapter 7 Use With Other Instruments

7-1 INTRODUCTION ...................7-3

7-2 MASTER-SLAVE OPERATION ...........7-4

Connecting the Instruments ...........7-4

Initiating Master-Slave Operation ........7-5

Master-Slave Operation .............7-7

Master-Slave Operation in VNA Mode ......7-7

Terminating Master-Slave Operation .......7-9

7-3 USE WITH A 56100ASCALAR NETWORK

ANALYZER......................7-10

Connecting the 681XXC to the 56100A .....7-10

7-4 USE WITH A 360B VECTOR NETWORK

ANALYZER......................7-11

Connecting the 681XXC to the 360B ......7-11

Modes of Operation...............7-12

Source Lock Mode ...............7-12

Tracking Mode .................7-14

7-5 USE WITH A HP8757D SCALAR NETWORK

ANALYZER......................7-16

Connecting the 681XXC to the HP8757D ....7-16

Setting Up the 681XXC.............7-17

Initiating HP8757D SNA Operation.......7-19

iv 681XXC OM

Table of Contents (Continued)

Appendix A Rear Panel Connectors

A-1 INTRODUCTION...................A-1

A-2 REAR PANEL CONNECTORS ...........A-1

A-3 CONNECTOR PINOUT DIAGRAMS ........A-1

Appendix B Performance Specifications

681XXC OM v/vi

Table of Contents (Continued)

Chapter 1 General Information

Table of Contents

1-1 SCOPE OF MANUAL.................1-3

1-2 INTRODUCTION ...................1-3

1-3 DESCRIPTION ....................1-3

1-4 IDENTIFICATION NUMBER ............1-5

1-5 ELECTRONIC MANUAL...............1-5

1-6 RELATED MANUALS ................1-5

GPIB Programming Manual ...........1-5

SCPI Programming Manual ...........1-5

Maintenance Manual ..............1-6

1-7 OPTIONS .......................1-6

1-8 PERFORMANCE SPECIFICATIONS ........1-7

1-9 RECOMMENDED TEST EQUIPMENT .......1-7

Figure 1-1. Series 681XXC Synthesized Signal Generator

Chapter 1 General Information

1-1 SCOPE OF MANUAL This manual provides general information, installation, and operating

information for the Anritsu Series 681XXC Synthesized Signal Gen erator. (Throughout this manual, the terms 681XXC and signal gen erator will be used interchangeably to refer to the instrument.) Man ual organization is shown in the table of contents.

1-2 INTRODUCTION This chapter contains general information about the series 681XXC

signal generators. It includes a general description of the instrument and information on its identification number, related manuals, op tions, and performance specifications. Alisting of recommended test equipment is also provided.

1-3 DESCRIPTION The Series 681XXC Synthesized Signal Generators are microproces-

sor-based, synthesized signal sources with high resolution phase-lock capability. They generate both broad (full range) and narrow band sweeps and discrete CW frequencies across the frequency range of 10 MHz to 65 GHz. All functions of the signal generator are fully controllable locally from the front panel or remotely (except for power on/standby) via the IEEE-488 General Purpose Interface Bus (GPIB).

The series presently consists of seven models covering a variety of fre quency and power ranges. Table 1-1, page 1-4, lists models, frequency ranges, and maximum leveled output.

681XXC OM 1-3

GENERAL 681XXC INFORMATION MODELS

Table 1-1. Series 681XXC Models

681XXC

Model

68117C 0.01 – 8.4 GHz +13.0 dBm +11.0dBm +9.0 dBm 68137C 2.0 – 20.0 GHz +13.0 dBm +11.0 dBm +3.0 dBm 68147C 0.01 – 20.0 GHz +13.0 dBm +11.0 dBm +3.0 dBm

68167C

68177C

68187C

68197C

Frequency Output Power

0.01 – 2.0 GHz

2.0 – 20.0 GHz

20.0 – 40.0 GHz

0.01 – 2.0 GHz

2.0 – 20.0 GHz

20.0 – 40.0 GHz

40.0 – 50.0 GHz

0.01 – 2.0 GHz

2.0 – 20.0 GHz

20.0 – 40.0 GHz

40.0 – 50.0 GHz

50.0 – 60.0 GHz

0.01 – 2.0 GHz

2.0 – 20.0 GHz

20.0 – 40.0 GHz

40.0 – 50.0 GHz

50.0 — 65.0 GHz

+13.0 dBm

+9.0 dBm +6.0 dBm

+11.0dBm +10.0 dBm

+2.5 dBm +2.5 dBm

+11.0dBm +10.0 dBm

+2.5 dBm +2.0 dBm +2.0 dBm

+11.0dBm +10.0 dBm

+2.5 dBm

0.0 dBm

–2.0 dBm

With Option 15A (High Power) Installed

Output Power

w/Step Attenuator

+11.0dBm +7.0 dBm +3.0 dBm

+10.0 dBm

+8.5 dBm

0.0 dBm

–1.0 dBm

+10.0 dBm

+8.5 dBm

0.0 dBm –1.5 dBm –2.0 dBm

Not Available Not Available

Output Power

w/Electronic

Step Attenuator

Not Available

68117C 68137C 2.0 – 20.0 GHz +17.0 dBm +15.0 dBm +7.0 dBm 68147C

68167C 68177C 0.01 – 50.0 GHz Standard Standard Not Available

68187C 0.01 – 60.0 GHz Standard Standard Not Available

Note: In models with Option 22 that have a high-end frequency of £20 GHz, rated output power is reduced by 1 dB

In models with Option 22 that have a high-end frequency of >20 GHz, rated output power is reduced by 2 dB.

0.01 – 2.0 GHz

2.0 – 8.4 GHz

0.01 – 2.0 GHz

2.0 – 20.0 GHz

0.01 – 20.0 GHz

20.0 – 40.0 GHz

+13.0 dBm +17.0 dBm

+13.0 dBm

+6.0 dBm

+11.0dBm +15.0 dBm

+11.0dBm

+3.0 dBm

Not Available

+11.0dBm +11.0dBm

+11.0dBm

+7.0 dBm

1-4 681XXC OM

GENERAL IDENTIFICATION INFORMATION NUMBER

1-4 IDENTIFICATION

NUMBER

All Anritsu instruments are assigned a unique six-digit ID number, such as “875012”. The ID number is imprinted on a decal that is af fixed to the rear panel of the unit. Special-order instrument configura tions also have an additional special serial number tag attached to the rear panel of the unit.

When ordering parts or corresponding with Anritsu Customer Service, please use the correct serial number with reference to the specific in strument’s model number (i.e., Model 68147C Synthesized Signal Gen erator, Serial No. 875012).

1-5 ELECTRONIC MANUAL This manual is available on CD ROM as an Adobe Acrobat Portable

Document Format (*.pdf) file. The file can be viewed using Acrobat Reader, a free program that is also included on the CD ROM. The file is “linked” such that the viewer can choose a topic to view from the displayed “bookmark” list and “jump” to the manual page on which the topic resides. The text can also be word-searched. Contact Anritsu Customer Service for price and availability.

1-6 RELATED MANUALS This is one of a four manual set that consists of an Operation Manual,

a GPIB Programming Manual, a SCPI Programming Manual, and a Maintenance Manual.

GPIB Programming Manual

SCPI Pro gramming Manual

This manual provides information for remote operation of the signal generator with 681XXC Product Specific commands sent from an external controller via the IEEE 488 General Purpose Interface Bus (GPIB). It contains a general description of the GPIB and bus data transfer and control functions, a complete listing and description of all 681XXC GPIB Product Specific commands, and several program ming examples. The Anritsu part number for the GPIB Programming Manual is 10370-10334.

This manual provides information for remote opera tion of the signal generator with Standard Com mands for Programmable Instruments (SCPI) commands sent from an external controller via the IEEE 488 General Purpose Interface Bus (GPIB). It contains a general description of the GPIB and bus data transfer and control functions, a complete list ing and description of each command in the 681XXC SCPI command set, and examples of command us age. The Anritsu part number for the SCPI Pro gramming Manual is 10370-10335.

681XXC OM 1-5

GENERAL INFORMATION OPTIONS

Maintenance Manual

The Maintenance Manual supplies service informa tion for all models in the 681XXC series. The service information includes functional circuit descriptions, block diagrams, performance verification tests, cali bration procedures, troubleshooting data, and as sembly and component removal/replacement procedures. The Anritsu part number for the Main tenance Manual is 10370-10336.

1-7 OPTIONS The following options are available.

Option 1, Rack Mounting. Rack mount kit containing a set of track slides (90° tilt capability), mounting ears, and front panel han dles for mounting the instrument in a standard 19-inch equipment rack.

Option 2A, 110 dB Step Attenuator. Adds a 10 dB per step attenuator with a 110 dB range for models having a high-end frequency of £20 GHz. Output power is selected directly in dBm on the front panel (or via GPIB). Rated RF output power is reduced.

Option 2B, 110 dB Step Attenuator. Adds a 10 dB per step attenuator with a 110 dB range for models having a high-end frequency of £40 GHz. Output power is selected directly in dBm on the front panel (or via GPIB). Rated RF output power is reduced.

Option 2C, 90 dB Step Attenuator. Adds a 10 dB per step attenuator with a 90 dB range for models having a high-end frequency of £50 GHz. Output power is selected directly in dBm on the front panel (or via GPIB). Rated RF output power is reduced.

Option 2D, 90 dB Step Attenuator. Adds a 10 dB per step attenuator with a 90 dB range for models having a high-end fre quency of £60 GHz. Output power is selected directly in dBm on the front panel (or via GPIB). Rated RF output power is reduced.

Option 2E, 120 dB Electronic Step Attenuator. Addsa10dB per step electronic attenuator with a 120 dB range for models hav ing a high-end frequency of £8.4 GHz. Output power is selected di rectly in dBm on the front panel (or via GPIB). Rated RF output power is reduced.

Option 2F, 120 dB Electronic Step Attenuator. Addsa10dB per step electronic attenuator with a 120 dB range for models hav ing a high-end frequency of £20 GHz. Output power is selected di rectly in dBm on the front panel (or via GPIB). Rated RF output power is reduced.

Option 9, Rear Panel RF Output. Moves the RF output connector to the rear panel.

Option 11, 0.1 Hz Frequency Resolution. Provides frequency resolution of 0.1 Hz.

1-6 681XXC OM

GENERAL PERFORMANCE INFORMATION SPECIFICATIONS

Option 14, Rack Mounting without Chassis Slides. Modifies rack mounting hardware to install unit in a console that has mount ing shelves. Includes mounting ears and front panel handles.

Option 15A, High Power Output. Adds high-power RF compo nents to the instrument providing increased RF output power in the 2–20 GHz frequency range. Option 15A is standard in models hav ing a high-end frequency that is >40 GHz.

Option 16, High-Stability Time Base. Adds an ovenized, 10 MHz crystal oscillator with <5 x 10

Option 17A, No Front Panel. Deletes the front panel for use in re mote control applications where a front panel display or keyboard control are not needed.

Option 18, mmWave Module Bias Output. Provides bias output for 54000-xWRxx Millimeter Wave Source Modules. BNC Twinax connector, rear panel.

Option 19, SCPI Programmability. Adds GPIB command mnemonics complying with Standard Commands for Programmable Instruments (SCPI), Version 1993.0. SCPI programming complies with IEEE 488.2-1987.

Option 22, 0.1 Hz to 10 MHz Audio Frequency. Adds frequency coverage below 10 MHz. In models having a high-end frequency of £20 GHz, rated output power is reduced by 1 dB; in models having a high-end frequency of >20 GHz, rated output power is reduced by 2 dB.

–10

/day frequency stability.

1-8 PERFORMANCE

SPECIFICATIONS

Series 681XXC Synthesized Signal Generator performance specifica tions are provided in Appendix B.

681XXC OM 1-7

GENERAL RECOMMENDED INFORMATION TEST EQUIPMENT

1-9 RECOMMENDED TEST

EQUIPMENT

Table 1-2 lists the recommended test equipment for performing the Se ries 681XXC Synthesized Signal Generator operation verification tests in Chapter 5.

Table 1-2. Recommended Test Equipment

Instrument Critical Specification Recommended Manufacturer/Model

Frequency Counter, with Cable Kit and External Mixer

Power Meter, with Power Sensors

Oscilloscope Bandwidth: DC to 150 MHz

Range: 0.01 to 65 GHz Input Z: 50W Resolution: 1Hz Other: External Time Base

Input

Range: –30 to +20 dBm (1 mW to 100 mW)

Vertical Sensitivity: 2 mV/ division Horiz Sensitivity: 50 ns/ division

EIP Microwave, Inc. Models 538B, 548B, or 578B, with Cable Kit: Option 590 and External Mixer:

Option 91 (26.5 to 40 GHz) Option 92 (40 to 60 GHz) Option 93 (60 to 90 GHz)

Anritsu Model ML2437Aor ML2438A, with Power Sensors:

MA2474A (0.01 to 40 GHz) MA2475A (0.01 to 50 GHz)

Tektronix, Inc. Model TAS485

1-8 681XXC OM

Chapter 2 Installation

Table of Contents

2-1 INTRODUCTION ...................2-3

2-2 INITIAL INSPECTION ................2-3

2-3 PREPARATION FOR USE ..............2-4

Power Requirements...............2-4

Line Voltage Selection ..............2-4

Power Connection ................2-4

Standby Operation................2-5

Warmup Time ..................2-6

Operating Environment .............2-6

2-4 GPIB SETUP AND INTERCONNECTION .....2-7

Interface Connector ...............2-7

Cable Length Restrictions ............2-7

GPIB Interconnection ..............2-7

Setting the GPIB Address ............2-7

Selecting the Line Terminator ..........2-9

Selecting the Interface Language.........2-9

2-5 RACK MOUNTING KIT INSTALLATION .....2-10

Preliminary ..................2-10

Procedure ...................2-10

2-6 PREPARATION FOR STORAGE/SHIPMENT . . . 2-13

Preparation for Storage.............2-13

Preparation for Shipment............2-13

Chapter 2 Installation

2-1 INTRODUCTION This chapter provides installation instructions for the Series 681XXC

Synthesized Signal Generator. It includes information on initial in spection, preparation for use, storage, and reshipment, and General Purpose Interface Bus (GPIB) setup and interconnections.

WARNING

Use two or more people to lift and move this equipment, or use an equipment cart. There is a risk of back injury, if this equipment is lifted by one person.

2-2 INITIAL INSPECTION Inspect the shipping container for damage. If the shipping container or

cushioning material is damaged, retain until the contents of the shipment have been checked against the packing list and the signal generator has been checked for mechanical and electrical operation.

If the shipment is incomplete or if the signal generator is damaged mechanically or electrically, notify your local sales representative or Anritsu Customer Service. If either the shipping container is damaged or the cushioning material shows signs of stress, notify the carrier as well as Anritsu. Keep the shipping materials for the carrier’s inspec tion.

681XXC OM 2-3

PREPARATION

INSTALLATION FOR USE

2-3 PREPARATION FOR USE Preparation for use consists of checking that the rear panel line volt

age selector switch is set for the correct line voltage and connecting the signal generator to the power source. The following paragraphs provide these procedures along with information about power require ments, warmup times, and the operating environment.

Power Requirements

Before applying power, verify that the unit is set to match the available line voltage and that the installed fuse is of the correct type and rating.

Line Voltage Selection

The signal generator accepts 90 to 132 Vac and 180 to 264 Vac, 48 to 440 Hz, single-phase power. Power consumption is 400 VA maximum. The signal gen erator is intended for Installation Category (Over voltage Category) II.

CAUTION

The line voltage selector switch on the rear panel can be set for either 110 Vac or 220 Vac operation (Figure 2-1). When the switch is set to 110 Vac, the 681XXC accepts 90 to 132 Vac line voltage. When the switch is set to 220 Vac, the 681XXC accepts 180 to 264 Vac line voltage. If the selector setting is incorrect for the line voltage available, change it to the correct setting.

Whenever the selector setting is changed, the line fuse must be changed to the correct value for the line voltage selected. Line fuse values for the line voltages are printed on the rear panel next to the fuse holder.

WARNING

Power Connection

Connecting the 681XXC to line power automatically places it in operation (front panel OPERATE LED on). To connect it to the power source, plug the fe male end of the power cable into the input line volt age receptacle on the rear panel (Figure 2-1). Then plug the male end of the power cord into a threewire power line outlet.

2-4 681XXC OM

PREPARATION

INSTALLATION FOR USE

Line Fuse

Line Voltage Selector Switch

GPIB

Connector

OPERATE

LINE

STANDBY

LEVEL

CONTROL

MODULATION

SYSTEM

Line Key

Figure 2-1. Signal Generator Rear Panel showing Power Connection

Standby Operation

Whenever the signal generator is not being used it should be left connected to the power source and placed in standby. This keeps the internal timebase frequency reference at operating temperature.

On the front panel, press LINE to switch the 681XXC from OPERATE (green LED on) to STANDBY (orange LED on).

NOTE

During standby operation, the fan runs continuously.

681XXC OM 2-5

PREPARATION

INSTALLATION FOR USE

Warmup Time

Operating Environment

From Standby–When placing the 681XXC in op eration from stand-by, allow 30 minutes warmup to assure stable operation.

From a Cold Start (0°C)–The signal generator re quires approximately 120 hours (5 days) of warm up to achieve specified frequency stability with aging.

NOTE

Instruments disconnected from AC power for more than 72 hours require 30 days to return to specified aging.

The 681XXC can be operated within the following environmental limits.

Temperature. 0°Cto50°C.

Humidity. 5 to 95% relative at 40°C.

Altitude. up to 4600 meters.

Cooling. Internal cooling is provided by forced

airflow from the fan mounted on the rear panel.

CAUTION

Before installing the 681XXC in its operating environment, ensure that all airflow passages at the sides and rear of the instrument are clear. This is of particular importance whenever the unit is being rack-mounted.

Keep the cooling fan filter clean so that the ventilation holes are not obstructed. A blocked fan filter can cause the instru ment to overheat and shut down.

2-6 681XXC OM

GPIB SETUP AND

INSTALLATION INTERCONNECTION

2-4 GPIB SETUP AND

INTERCONNECTION

The 681XXC provides automated microwave signal generation via the GPIB. The following paragraphs provide information about interface connections, cable requirements, setting the GPIB operating parame ters, and selecting the external interface language.

Interface Connector

Cable Length Restrictions

Interface between the signal generator and other de vices on the GPIB is via a 24-wire interface cable. This cable uses connector shells having two connec tor faces. These double-faced connectors allow for the parallel connection of two or more cables to a single device. Figure 2-1 shows the location of the rear panel GPIB connector.

The GPIB can accommodate up to 15 instruments at any one time. To achieve design performance on the bus, proper timing and voltage level relationships must be maintained. If either the cable length be tween separate instruments or the cumulative cable length between all instruments is too long, the data and control lines cannot be driven properly and the system may fail to perform. Cable length restrictions are as follows:

No more than 15 instruments may be installed on the bus.

Total cumulative cable length in meters may not exceed two times the number of bus instruments or 20 meters—whichever is less.

NOTE

For low EMI applications, the GPIB cable should be a fully shielded type, with well-grounded metal-shell connectors

GPIB Inter connection

Setting the GPIB Address

The only interconnection required for GPIB opera tion is between the signal generator and the control ler. This interconnection is via a standard GPIB cable. The Anritsu Part number for such a cable is 2000-1, -2, or -4 (1, 2, or 4 meters in length).

The default GPIB address is 5. If a different GPIB address is desired, it can be set from the front panel using the Configure GPIB Menu.

To change the GPIB address, first press the front panel main menu key labeled SYSTEM . The Sys tem Menu (shown on the following page) is dis played.

681XXC OM 2-7

GPIB SETUP AND

INSTALLATION INTERCONNECTION

Now press the menu soft-key Config . The System Configuration Menu (below) is displayed.

To go to the Configure GPIB menu from this menu, press the menu soft-key GPIB . The Configure GPIB Menu (below) is displayed.

Press the menu soft-key GPIB Address to change the current GPIB address of the signal generator. Enter a new address using the cursor control key or the data entry keypad and the terminator key

ADRS

The new GPIB address will now appear on the dis play. The entry must be between 1 and 30 to be rec ognized as a valid GPIB address.

2-8 681XXC OM

GPIB SETUP AND

INSTALLATION INTERCONNECTION

Selecting the Line Terminator

Selecting the Interface Language

Data is delimited on the GPIB by either the carriage return (CR) ASCII character or both the carriage re turn and line feed (CR/LF) ASCII characters. Which character is used depends upon the requirements of the system controller. Most modern controllers can use either CR or CR/LF, while many older control lers require one or the other. Consult the controller’s manual for its particular requirements.

From the Configure GPIB Menu display, you can se lect which GPIB terminator to use by pressing the menu soft-key Line Term . This menu soft-key tog gles the GPIB terminator between CR and CR/LF. The current selection appears on the display.

Series 681XXC Synthesized Signal Generators can be remotely operated via the GPIB using one of two external interface languages—Native or SCPI (Op tion 19). The Native interface language uses a set of 681XXC GPIB Product Specific commands to control the instrument; the SCPI interface language uses a set of the Standard Commands for Programmable Instruments commands to control the unit.

The Configure GPIB Menu has additional menu displays. For instruments with Option 19, selection of which external interface language is to be used is made from this additional menu. From the Configure GPIB Menu display, you can access the first additional menu by pressing More . The first Addi tional Configure GPIB Menu (below) is displayed.

Press Native SCPI to select the external interface language to be used. This menu soft-key toggles the language selection between Native and SCPI. The current selection appears on the display.

681XXC OM 2-9

RACK MOUNTING KIT

INSTALLATION INSTALLATION

2-5 RACK MOUNTING KIT

INSTALLATION

The rack mounting kit (Option 1) contains a set of track slides (90° tilt capability), mounting ears, and front panel handles for mounting the signal generator in a standard equipment rack. The following proce dure provides instructions for installing the rack mounting hardware on to the instrument. Refer to Figures 2-2 and 2-3 during this proce dure.

Preliminary Disconnect the power cord and any other cables

from the instrument.

Procedure Install the rack mounting hardware as follows:

Step 1 Using a Phillips screwdriver, remove the

screws and the front handle assemblies from the instrument. (For instruments not having front handles, remove the screws and the front top and bottom feet from the instrument.) Retain the screws.

Step 2 Remove the four feet from the rear of the

instrument. Retain the screws.

Step 3 Remove the screws and the carrying han-

dle from the side handle cover. (The two screws fastening the carrying handle through the side handle cover to the chassis are accessable by lifting up the rubber covering at each end of the handle.)

Figure 2-2. Front Handle, Feet, and Carrying Handle Removal

2-10 681XXC OM

RACK MOUNTING KIT

INSTALLATION INSTALLATION

Step 4 Remove the inner slide assemblies from

the outer slide assemblies.

Step 5 Place the left side inner slide assembly

NOTE

The screws with green heads have metric threads. When it becomes necessary to replace any of these screws, always use the exact re placement green-headed screws (Anritsu P/N 2000-560) to avoid damage to the instrument.

Step 6 Insert two green-headed screws through

Step 7 Insert two green-headed screws through

onto the instrument case with the handle towards the front of the instrument (Fig ure 2-3).

the holes in the slide assembly behind the handle and into the metric tapped holes in the side of the instrument.

the holes near the rear of the slide assem bly and into the metric tapped holes in the side of the instrument.

Step 8 Insert the two SAE threaded screws (re

moved from the feet) through the 90° tabs on the rear of the slide assembly and into the rear panel of the instrument.

Step 9 Using the Phillips screwdriver, tighten all

screws holding the left side slide assembly to the instrument chassis.

Figure 2-3. Rack Mounting Hardware Installation

681XXC OM 2-11

RACK MOUNTING KIT

INSTALLATION INSTALLATION

Step 10 Place the right side inner slide assembly

onto the instrument case with the handle towards the front of the instrument.

Step 11 Insert two green-headed screws through

the holes in the slide assembly behind the handle and into the metric tapped holes in the side of the instrument.

Step 12 Insert two green-headed screws through

the holes near the rear of the slide assem bly and into the metric tapped holes in the side of the instrument.

Step 13 Insert the two SAE threaded screws (re

moved from the feet) through the 90° tabs on the rear of the slide assembly and into the rear panel of the instrument.

Step 14 Using the Phillips screwdriver, tighten all

screws holding the right side slide assembly to the instrument chassis.

Step 15 With the appropriate hardware, install

the outer slide assemblies onto the equipment rack.

Step 16 Lift the signal generator into position.

Align the inner and outer slide assemblies and slide the instrument into the rack. Realign the hardware as needed for smooth operation.

WARNING

Use two or more people to lift and move this equipment, or use an equipment cart. There is a risk of back injury, if this equipment is lifted by one person.

2-12 681XXC OM

PREPARATION FOR

INSTALLATION STORAGE/SHIPMENT

2-6 PREPARATION FOR

STORAGE/SHIPMENT

The following paragraphs give instructions for preparing the 681XXC for storage or shipment.

Preparation for Storage

Preparation for Shipment

Preparing the signal generator for storage consists of cleaning the unit, packing the inside with mois ture-absorbing desiccant crystals, and storing the unit in a temperature environment that is main tained between –40°C and +75°C.

To provide maximum protection against damage in transit, the signal generator should be repackaged in the original shipping container. If this container is no longer available and the unit is being returned to Anritsu for repair, advise Anritsu Customer Serv ice; they will send a new shipping container free of charge. In the event neither of these two options is possible, instructions for packaging and shipment are given below.

Use a Suitable Container.

Obtain a corrugated cardboard carton with a 125 kg test strength. This carton should have inside dimensions of no less than 15 cm larger than the unit dimensions to allow for cushioning.

Protect the Instrument.

Surround the unit with polyethylene sheeting to protect the finish.

Cushion the Instrument.

Cushion the instrument on all sides by tightly pack ing dunnage or urethane foam between the carton and the unit. Provide at least three inches of dun nage on all sides.

Seal the Container.

Seal the carton by using either shipping tape or an industrial stapler.

Address the Container.

If the instrument is being returned to Anritsu for service, mark the address of the appropriate Anritsu service center (Table 2-1) and your return address on the carton in one or more prominent locations.

681XXC OM 2-13

ANRITSU

INSTALLATION SERVICE CENTERS

Table 2-1. ANRITSU Service Centers

UNITED STATES

ANRITSU COMPANY 490 Jarvis Drive Morgan Hill, CA 95037-2809 Telephone: (408) 776-8300 1-800-ANRITSU FAX: 408-776-1744

ANRITSU COMPANY 10 New Maple Ave., Unit 305 Pine Brook, NJ 07058 Telephone: (201) 227-8999, 1-800-ANRITSU FAX: 201-575-0092

ANRITSU COMPANY 1155E. Collins Blvd Richardson, TX 75081 Telephone: 1-800-ANRITSU FAX: 972-671-1877

AUSTRALIA

ANRITSU PTY. LTD. Unit 3, 170 Foster Road Mt Waverley, VIC 3149 Australia Telephone: 03-9558-8177 FAX: 03-9558-8255

BRAZIL

ANRITSU ELECTRONICA LTDA. Praia de Botafogo, 440, Sala 2401 CEP22250-040, Rio de Janeiro, RJ, Brasil Telephone: 021-527-6922 FAX: 021-53-71-456

CANADA

ANRITSU INSTRUMENTS LTD. 215 Stafford Road, Unit 102 Nepean, Ontario K2H 9C1 Telephone: (613) 828-4090 FAX: (613) 828-5400

CHINA

ANRITSU ELECTRONICS (SHANGHAI) CO. LTD. 2F, Rm B 52 Section Factory Building No. 516 Fu Te Rd (W) Shanghi 200131 China Telephone: 21-58680226, 58680227 FAX: 21-58680588

FRANCE

ANRITSU S.A 9 Avenue du Quebec Zone de Courtaboeuf 91951 Les Ulis Cedex Telephone: 016-09-21-550 FAX: 016-44-61-065

GERMANY

ANRITSU GmbH Grafenberger Allee 54-56 D-40237 Dusseldorf, Germany Telephone: 0211-968550 FAX: 0211-9685555

INDIA

MEERA AGENCIES (P) LTD. 23 Community Center Kailash Colony Extension New Delhi, India Telephone: 91-11-6442700 FAX: 91-11-6442500

ISRAEL

TECH-CENT, LTD. 4 Raul ValenbergSt Tel-Aviv 69719 Telephone: (03) 64-78-563 FAX: (03) 64-78-334

ITALY

ANRITSU Sp.A Roma Office Via E. Vittorini, 129 00144 Roma EUR Telephone: (06) 50-99-711 FAX: (06) 50-22-4252

KOREA

ANRITSU CORPORATIONLTD. 8F, Seocho-Dong, Secho-Ku Seoul, 137-070

South Korea Telephone: 2-581-6603 FAX: 2-582-6603

JAPAN

ANRITSU CUSTOMER SERVICE LTD. 1800 Onna Atsugi-shi Kanagawa-Prf. 243 Japan Telephone: 0462-96-6688 FAX: 0462-25-8379

SINGAPORE

ANRITSU (SINGAPORE) PTE LTD. 6 New Industrial Road #06-01/02 Hoe Huat Industrial Bldg Singapore 536199 Telephone: 282-2400 FAX: 282-2533

SOUTH AFRICA

ETECSA 12 Surrey Square Office Park 330 Surrey Avenue Ferndale, Randburt, 2194 South Africa Telephone: 011-27-11-787-7200 FAX: 011-27-11-787-0446

SWEDEN

ANRITSU AB Botivid Center Fittja Backe 13A S145 84 Stockholmn Telephone: (08) 534-707-00 FAX: (08) 534-707-30

TAIWAN

ANRITSU CO., LTD. 6F, No. 96, Section 3 Chien Kuo N. Road Taipei, Taiwan, R.O.C. Telephone: (02) 515-6050 FAX: (02) 509-5519

UNITED KINGDOM

ANRITSU LTD. 200 Capability Green Luton, Bedfordshire LU1 3LU, England Telephone: 015-82-433200 FAX: 015-82-731303

2-14 681XXC OM

Chapter 3 Local (Front Panel) Operation

Table of Contents

3-1 INTRODUCTION ...................3-5

3-2 FRONT PANEL LAYOUT...............3-6

Line Key ....................3-6

Data Display Area ................3-6

Data Entry Area.................3-7

RF Output Control Key .............3-7

Connectors ...................3-7

3-3 DATA DISPLAY AREA ................3-8

Menu Display Format ..............3-9

Menu Keys ...................3-10

3-4 DATA ENTRY AREA.................3-12

3-5 INSTRUMENT START-UP .............3-14

Powering Up the 681XXC............3-14

Start-Up Display ................3-14

Standby Operation ...............3-14

Self-Testing the 681XXC ............3-15

Resetting to Default Parameters ........3-15

3-6 ENTERING DATA ..................3-18

Opening the Parameter.............3-18

Editing the Current Value ...........3-19

Entering a New Value .............3-20

Table of Contents (Continued)

3-7 CW FREQUENCY OPERATION ..........3-21

Selecting CW Mode...............3-21

Selecting a CW Frequency ...........3-22

Selecting a Power Level.............3-24

CW Ramp ...................3-25

3-8 SWEEP FREQUENCY OPERATION........3-26

Analog Sweep Mode ..............3-26

Selecting Analog Sweep Mode..........3-26

Setting the Analog Sweep Time.........3-27

Selecting a Sweep Trigger ...........3-28

Step Sweep Mode................3-29

Selecting Step Sweep Mode ...........3-29

Setting Step Size, Dwell Time, and Sweep Time. 3-29

Manual Sweep Mode ..............3-32

Selecting Manual Sweep Mode .........3-32

Selecting a Sweep Range ............3-33

Selecting a Power Level.............3-35

Frequency Markers...............3-36

Selecting Alternate Sweep Mode ........3-38

List Sweep Mode ................3-41

Selecting List Sweep Mode ...........3-42

Editing the List ................3-43

Selecting a List Sweep Range..........3-46

Selecting a List Sweep Trigger .........3-47

3-9 FIXED POWER LEVEL OPERATION .......3-49

Selecting Fixed Power Level Mode .......3-49

Selecting a Power Level.............3-49

Level Offset ..................3-52

3-10 POWER LEVEL SWEEP OPERATION.......3-53

Selecting CW Power Sweep Mode ........3-53

Setting CW Power Sweep Step Size and

Dwell Time ..................3-54

Selecting a CW Power Sweep Trigger ......3-55

Selecting a Power Level Sweep Range......3-56

Selecting a Sweep Frequency/Step Power Mode . 3-58

Setting Power Level Step Size .........3-59

3-2 681XXC OM

Table of Contents (Continued)

3-11 LEVELING OPERATIONS .............3-60

Selecting a Leveling Mode ...........3-60

Attenuator Decoupling .............3-64

ALC Power Slope................3-65

User Cal (User Level Flatness Correction) . . . 3-67

3-12 SIGNAL MODULATION ..............3-73

Amplitude Modulation Operating Modes ....3-73

Providing Amplitude Modulation ........3-73

Frequency Modulation Operating Modes ....3-74

Providing Frequency Modulation ........3-75

Square Wave Modulation Operating Modes . . . 3-77

Providing Square Wave Modulation .......3-77

3-13 SYSTEM CONFIGURATION ............3-80

Configuring the Front Panel ..........3-81

Configuring the Rear Panel...........3-82

Configuring the RF ...............3-83

Configuring the GPIB .............3-85

Setting Increment Sizes ............3-88

3-14 SAVING/RECALLING INSTRUMENT SETUPS . 3-89

Saving Setups .................3-89

Recalling Setups ................3-89

Erasing Stored Setups .............3-90

3-15 SECURE OPERATION ...............3-91

3-16 REFERENCE OSCILLATOR CALIBRATION . . . 3-92

681XXC OM 3-3

Chapter 3 Local (Front Panel) Operation

3-1 INTRODUCTION This chapter provides information and instructions on operating the

Series 681XXC Synthesized Signal Generator using the front panel controls. It contains the following:

Illustrations and diagrams of the front panel, data display area,

and data entry area that identify and describe all front panel controls, inputs, and outputs.

An annotated diagram of the menu display format showing

where the current frequency, power, and modulation information is displayed.

Instructions for performing signal generator operations; namely,

frequency and frequency sweep, power level and power sweep, signal modulation, saving and recalling instrument setups, and system configuration.

681XXC OM 3-5

LOCAL (FRONT FRONT PANEL PANEL) OPERATION LAYOUT

3-2 FRONT PANELLAYOUT The 681XXC front panel is divided into two main areas—the data dis

play area and the data entry area. The following paragraphs provide a brief description of the front panel controls, inputs, outputs, and data display and data entry areas as shown in Figure 3-1. Detailed descrip tions of the data display and data entry areas are contained in para graphs 3-3 and 3-4.

R F O u t p u t

C o n t r o l

K e y

O u t p u t

O f f

O n

R F O u t p u t

5 0

C A U T I O N

R F O u t p u t

M a y E x c e e d 1 0 0 m W

S y n t h e s i z e d S i g n a l G e n e r a t o r

O p e r a t e

L i n e

S t a n d b y

C W / S W E E P

S E L E C T

F R E Q U E N C Y

C O N T R O L

L E V E L / A L C

S E L E C T

L E V E L

C O N T R O L

M O D U L A T I O N

S Y S T E M

D a t a D i s p l a y D a t a E n t r y

C l e a r E n t r y

M o d u l a t i o n

F M I n

A M I n

E x t e r n a l A L C I n

I n

B a c k

G H z

S p a c e

2 31

S e c d B m

M H z

m s

d B

654

k H z

S t e p

H z

n s

A d r s

L i n e

K e y

M e n u

K e y s

Figure 3-1. Front Panel, 681XXC Synthesized Signal Generator

Line Key

The line key provides for turning the signal genera tor on and off. STANDBY (off) is indicated by an or ange LED; OPERATE (on) by a green LED.

Data Display Area

The data display area consists of the data display and the surrounding menu keys.

Data Display

The data display provides information about the current status of the 681XXC in a menu display for mat. This information includes the operating mode of the instrument, the value of the active frequency and power level parameters, and the modulation status.

Menu Keys

Menu keys provide for selecting the operating mode, parameters, and configuration of the signal genera tor.

M o d u l a t i o n

C o n n e c t o r s

E x t e r n a l

A L C

C o n n e c t o r

R F O u t p u t C o n n e c t o r

3-6 681XXC OM

LOCAL (FRONT FRONT PANEL PANEL) OPERATION LAYOUT

Data Entry Area

RF Output Control Key

Connectors The front panel has both input and output connec

The data entry area consists of data entry keys and controls that provide for (1) changing values for each 681XXC parameter, and (2) terminating the value entry and assigning the appropriate units (GHz, MHz, dBm, etc.).

The RF output control key provides for turning the RF output power on and off. OUTPUT OFF is indi cated by a red LED; OUTPUT ON by a yellow LED.

tors.

Modulation Connectors

The modulation connectors provide for applying ex ternal AM, FM, or Square Wave modulation to the RF output signal.

External ALC Connector

The external ALC connector provides for leveling the RF output signal externally using either a detector or a power meter.

RF Output Connector

The RF output connector provides RF output from a 50W source.

NOTE

To prevent power losses due to an imped ance mismatch, the mating connector and cable should also be rated at 50W.

681XXC OM 3-7

LOCAL (FRONT DATA DISPLAY

PANEL) OPERATION AREA

3-3 DATA DISPLAY AREA The data display area consists of the data display and the surrounding

menu keys. The data display is a dot matrix liquid crystal display (LCD) that provides 16 lines of 40 characters each. Information is pre sented on the LCD in the form of menu displays. The menu keys ei ther select the main menu to be displayed, select a sub-menu of the current menu display, or control a function on the current menu dis play.

Figure 3-2 shows the format of the menu display and identifies the display elements. It also shows the placement of the menu keys in re lation to the display. The paragraphs that follow provide descriptions of the menu display elements and the menu keys.

Main Menu

Keys

MODULATION

Main Menu Key Cursor

CW/SWEEP

SELECT

FREQUENCY

CONTROL

LEVEL/ALC

SELECT

LEVEL

CONTROL

SYSTEM

Frequency

Mode

Title Bar

Modulation

Title Bars

Frequency

Parameters

Area

Level Mode

Title Bar

Level

Parameters

Area

Labels

Side Keys

Soft-Keys

Modulation

Status Areas

Figure 3-2. Front Panel Data Display Area

Soft-Keys

Menu Labels Bottom Ke

3-8 681XXC OM

LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA

Menu Display Format

The menu display is divided into specific areas that show the frequency, power level, and modulation in formation for the current signal generator setup. Menu labels for the current menu’s soft-keys appear along the bottom and right side of the display.

Title Bars

A shaded title bar identifies each parameter area. Mode information is displayed in reverse video on the title bars.

Frequency Mode Title Bar—The current

frequency mode (CW, Analog Sweep, Step Sweep, Manual Sweep, or List Sweep) appears on the left side of the bar. In an analog, step, or list sweep mode, the type of sweep trigger ap

pears on the right side. Level Mode Title Bar—The current power

level mode (Level or Level Sweep) appears on the left side of the bar. In a level sweep mode, the type of sweep trigger appears on the right side of the bar. Modulation Title Bars—Each type of signal

modulation (AM, FM, Square Wave) has a separate title bar on the display.

Parameter Areas

The parameter areas show the frequency, power level, and modulation information for the current 681XXC setup.

Frequency Parameters Area—The current CW frequency in GHz, the start and stop fre

quencies of the current frequency sweep range in GHz, the current list index and frequency, or the start and stop indexes for the list sweep are displayed in this area.

Power Level Parameters Area—The cur

rent power level in dBm or mV, or the start and stop levels of the current power level sweep range in dBm or mV are displayed in this area.

Modulation Status Areas—These areas dis

play ON or OFF to indicate the status of signal modulation for the current setup.

Menu Labels

Each of the menu soft-keys, located below and to the right of the display, has a corresponding menu label area on the display. These labels identify the func

tion of the soft-keys for the current menu display. In

681XXC OM 3-9

LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA

most cases, when a menu soft-key is pressed, its menu label changes appearance to visually show the On/Off condition.

Window Display

A window display that overlays a portion of the cur rent menu display is used to (1) show the parameter being edited; (2) display selection lists of preset fre quencies, power levels, markers, etc.; (3) show the modulation and system configuration choices and current selections; or (4) show self-test error mes sages. Atypical window display is shown on the left.

Menu Keys As shown in Figure 3-2, there are two types of menu

keys that surround the data display—main menu keys and menu soft-keys. The main menu keys are positioned to the left of the data display. The menu soft-keys are located at the bottom and to the right of the data display.

CW/SWEEP

SELECT

FREQUENCY

CONTROL

LEVEL/ALC

SELECT

LEVEL

CONTROL

MODULATION

SYSTEM

Main Menu Keys

Each of the main menu keys, shown on the left, selects a main (top-level) menu display. These menus let you select the operating mode, operating parameters, and configuration of the instrument. A brief functional description of each main menu follows.

CW/SWEEP SELECT—This menu lets you select between CW, Analog, Step, Manual, and List Sweep frequency modes.

FREQUENCY CONTROL—In CW frequency mode, this menu lets you select the CW fre

quency parameter (F0-F9 or M0-M9) to use. In the Analog, Step, or Manual Sweep frequency mode, this menu lets you select the sweep range parameters (Full, F1-F2, F3-F4, F5-dF, or F6-dF) to use. In Analog or Step Sweep fre quency mode, the menu also lets you select up to 20 independent, pre-settable frequency markers.

LEVEL/ALC SELECT—This menu lets you select power level and ALC modes (Level, Level Sweep, Level Offset, ALC on or off, inter nal or external ALC, ALC/attenuator decou pling, ALC slope, and user level flatness cor

rection).

LEVEL CONTROL—In Level mode, this menu lets you select the level parameter (L0L9) to use for a CW frequency or a frequency

3-10 681XXC OM

LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA

sweep. In the Level Sweep mode, this menu lets you select the power sweep range parame ters to use. MODULATION—This menu provides you

with access to sub-menus that let you select the type of signal modulation (AM, FM, or Square Wave) and control the option settings for each type. SYSTEM—This menu provides you with ac

cess to sub-menus that let you (1) reset the in strument to factory-selected default values; (2) configure the front panel, rear panel, RF, and GPIB; (3) set incremental sizes for editing fre quency, power level, and time parameters; (4) save or recall instrument setups; (5) disable front panel data display; (6) perform instru ment self-test; and (7) perform reference oscil lator calibration.

CW/SWEEP

SELECT

FREQUENCY

CONTROL

LEVEL/ALC

SELECT

CONTROL

MODULATION

SYSTEM

Main Menu Key Cursor

With the exception of the SYSTEM key, when any main menu key is pressed, the main menu that is displayed contains a cursor positioned adjacent to the pressed key (Figure 3-2). The cursor is displayed on all sub-menus of the current menu until a different main menu key is pressed.

When the SYSTEM key is pressed, the System menu is displayed. The System menu and its submenus do not contain a main menu key cursor.

Menu Soft-Keys

As shown on the left, five menu soft-keys are located below the data display and five menu soft-keys are located to the right of the data display. In general, the menu soft-keys located below the data display

LEVEL

select a sub-menu of the current main (top-level) menu display; the menu soft-keys located to the right of the data display either control a function on the current menu display or select an additional sub-menu. Menu labels that identify the current function of each soft-key are shown on the menu dis

play adjacent to the soft-keys.

681XXC OM 3-11

LOCAL (FRONT DATA ENTRY PANEL) OPERATION AREA

3-4 DATA ENTRYAREA The value of a selected 681XXC parameter can be changed using the

rotary data knob and/or keys of the data entry area. Each element of the data entry area is identified in Figure 3-3 and described in the fol lowing paragraphs.

Cursor

Control

Key

Rotary

Data

Knob

Figure 3-3. Front Panel Data Entry Area

Clear Entry

Key

CLEAR ENTRY

Space

Keypad

Back

Key

BACK

SPACE

Terminator

Keys

GHz

Sec

dBm

MHz

kHz

STEPS

ADRS

Cursor Control Key

In general, this diamond-shaped key controls the movement of the cursor on the display. When a pa rameter is opened for editing, a cursor appears un

der the open parameter. Each time the < or > pad is pressed, the cursor moves left or right by one digit. The Ù or Ú pad can then be used to increase or de

crease the value of the parameter. The unit size of the increase or decrease that occurs each time the Ù or Ú pad is pressed is determined by the cursor posi tion.

In addition, when editing frequency, power level, and time parameters, the incremental size can be set to a specific value using the system configura

tion increment menu (paragraph 3-13). Once set and activated, each time the Ù or Ú pad is pressed, the parameter’s value increases or decreases by the set amount.

3-12 681XXC OM

LOCAL (FRONT DATA ENTRY PANEL) OPERATION AREA

Rotary Data Knob

The rotary data knob can be used to change the value of a parameter that is open for editing. The cursor is moved under the open parameter using the < and > pads of the cursor control key. Then, by slowly turning the knob clockwise or counterclockwise the value of the parameter is increased or decreased by the unit size. The unit size is deter mined by the cursor placement. Turning the knob rapidly changes the value of the parameter in larger steps.

NOTE

When Linear power level units are selected, use the followingtermina tor keys for power level data entries.

GHz / Sec / dBm for V MHz/ms/dBfor mV kHz / ms / STEPS for mV

When editing frequency, power level, and time pa rameters, the incremental size can be set to a spe cific value using the system configuration increment menu (paragraph 3-13). Once set and activated, each time the knob is turned clockwise or counterclockwise, the param-eter’s value increases or de creases by the set amount.

KEYPAD

The numeric keypad provides for entering frequency, power level, time, and number-of-steps parameters and GPIB address values. The “–” key functions as a “change sign” key during any keypad entry.

CLEAR ENTRY Key

When a parameter is open for editing, the CLEAR ENTRY key is used to clear the parameter entry.

BACK SPACE Key

The BACK SPACE key is used to correct keypad data entry errors by deleting the last number, “–”, or decimal point entered.

Terminator Keys

The terminator keys are used to terminate keypad data entries and change the parameter values in memory. If the entered value is outside the allow

able range of the open parameter, an error message will be displayed along with an audible “beep”. The terminator keys are as follows:

GHz / Sec / dBm MHz/ms/dB kHz / ms / STEPS Hz / ns / ADRS

681XXC OM 3-13

LOCAL (FRONT INSTRUMENT PANEL) OPERATION START-UP

3-5 INSTRUMENT START-UP Now that you have familiarized yourself with the layout of the signal

generator’s front panel controls and data display, you are ready to be gin operating the instrument. Begin by powering it up.

LEVEL

CONTROL

MODULATION

SYSTEM

Powering Up the 681XXC

Start-Up Display

Standby Operation

Connect the 681XXC to an ac power source by fol

lowing the procedure in the Installation chapter. This automatically places the instrument in opera

tion (front panel OPERATE LED on). During power up, the message Please Wait...

LOADING PROGRAMS appears on the data display. When all programs have been loaded, the start-up screen (below) is displayed. It provides you with the model number of the signal generator and the revi sion level of the installed firmware.

The 681XXC then returns to the exact configuration it was in when last turned off.

Whenever the signal generator is not being used, it should be left connected to the power source and placed in standby. Standby operation provides power to keep the internal time base at operating temperature. This assures specified frequency accu racy and stability when the 681XXC is place in op

eration.

OPERATE

LINE

STANDBY

During standby operation, the fan runs continuously.

NOTE

Press LINE to switch the 681XXC from OPERATE

Line

(green LED on) to STANDBY (orange LED on).

Key

NOTE

When switching to operate from standby, allow at least a 30-minute warmup before beginning signal generator operations.

3-14 681XXC OM

LOCAL (FRONT INSTRUMENT PANEL) OPERATION START-UP

Self-Testing the 681XXC

During self-test with RF OUTPUT set to ON, the output power level is set to 0 dBm. Always disconnect sensitive equipment from the unit before performing self-test.

The 681XXC firmware includes internal diagnostics that self-test the instrument. These self-test diag nostics perform a brief go/no-go test of most of the PCBs and other internal assemblies. If the signal generator fails self-test, an error message is dis played on the data display. Error messages and de scriptions are listed in the Operator Maintenance chapter of this manual.

CAUTION

You can perform a self-test of the signal generator at any time during normal operation. To perform a self-test from any menu, press SYSTEM . Then, when the System Menu (below) is displayed, press

Selftest .

Resetting to Default Parameters

You can reset the 681XXC to the factory-selected default parameter values at any time during normal operation. The default parameters are shown in Table 3-1 on the following page.

NOTE

Resetting the instrument clears the setup presently in place. If these parameter val ues are needed for future testing, save them as a stored setup before resetting the signal generator. (For information on saving/recalling instrument setups, refer to paragraph 3-14.)

To reset the signal generator, press SYSTEM . When the System Menu (above) is displayed, press

Reset .

681XXC OM 3-15

LOCAL (FRONT RESET (DEFAULT) PANEL) OPERATION PARAMETERS

Table 3-1. Reset (Default) Paramenters (1 of 2)

681XXC MODEL

NUMBER

68117C 3.5 2.0 8.4 2.0 5.0 8.0 8.4 8.4 8.4 8.4 3.5 2.0 8.4 2.0 5.0 8.0 8.4 8.4 8.4 8.4 1.0 68137C 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68147C 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68167C 3.5 2.0 40.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 40.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68177C 3.5 2.0 50.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 50.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68187C 3.5 2.0 60.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 60.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68197C 3.5 2.0 65.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 65.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0

F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 M0 M1 M2 M3 M4 M5 M6 M7 M8 M9 DF

FREQUENCY PARAMETERS (GHz)

681XXC MODEL

NUMBER

68117C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0 68137C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0 68147C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0 68167C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0 68177C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0 68187C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0 68197C +1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –6.0 –7.0 –8.0

L0 L1 L2 L3 L4 L5 L6 L7 L8 L9

POWER LEVEL PARAMETERS (dBm)

3-16 681XXC OM

LOCAL (FRONT RESET (DEFAULT) PANEL) OPERATION PARAMETERS

Table 3-1. Reset (Default) Paramenters (2 of 2)

681XXC

MODEL

NUMBER

68117C 50 ms 1 ms 50 50 ms 50 0.0 dB 68137C 50 ms 1 ms 50 50 ms 50 0.0 dB 68147C 50 ms 1 ms 50 50 ms 50 0.0 dB 68167C 50 ms 1 ms 50 50 ms 50 0.0 dB 68177C 50 ms 1 ms 50 50 ms 50 0.0 dB 68187C 50 ms 1 ms 50 50 ms 50 0.0 dB 68197C 50 ms 1 ms 50 50 ms 50 0.0 dB

SWEEP

TIME

DWELL TIME

STEP SWEEP LEVEL SWEEP

NUMBER OF

STEPS

DWELL TIME

NUMBER OF

STEPS

LEVEL

OFFSET

681XXC OM 3-17

LOCAL (FRONT ENTERING PANEL) OPERATION DATA

3-6 ENTERING DATA Before proceeding to the various modes of signal generator operation,

you need to know how to enter data from the front panel. Entering data refers to changing a parameter’s value by editing its current value or entering a new value to replace the current value. The follow ing instructions describe how to (1) open a parameter, (2) edit its cur rent value, and (3) enter a new value.

A typical 681XXC menu display (below) is used throughout the data entry instructions. At this menu display, you can edit both the CW fre quency and the output power level parameters.

If you wish to follow along on your 681XXC, you can obtain this same menu display by resetting your instrument (press SYSTEM , then press Reset ).

Opening the Parameter

In order for the value of a parameter to be changed, the parameter must first be opened.

To open the frequency parameter from the above menu, press Edit F1 . The menu display now changes to show that the menu soft-key Edit F1 has been pressed and that the frequency parameter has been opened. An open parameter is indicated by placing it in a window with a movable cursor under its digits.

Only one parameter can be open at a time. If you press Edit L1 then the frequency parameter will close and the power level parameter will open.

3-18 681XXC OM

LOCAL (FRONT ENTERING PANEL) OPERATION DATA

Cursor

Control

Key

Rotary

Data

Knob

Editing the Current Value

To change the current value of a parameter by edit

ing, you can use either the cursor control key or the rotary data knob.

Using the Cursor Control Key

Using the < and > pads of the cursor control key, move the cursor under the digit where you want to begin editing. Then increase or decrease the value of the parameter using the Ù or Ú pad of the cursor control key. The unit size of the increase or decrease that occurs each time the Ù or Ù pad is pressed is de termined by the cursor position.

Using the Rotary Data Knob

You can also increase or decrease the value of the parameter using the rotary data knob. Once you have positioned the cursor under the digit where you want to begin editing, slowly turn the knob clockwise or counter-clockwise to increase or decrease the value of the parameter by the unit size. Turning the knob rapidly changes the value of the parameter in larger steps.

Using a Set Increment

When editing frequency, power level, and time parameters, you can increase or decrease the parameter’s value by a set amount each time the Ù or Ú pad is pressed or the rotary data knob is turned clockwise or counter-clockwise. For instructions on set

ting the increment size, refer to paragraph 3-13.

Now, try changing the current value of the CW fre

quency displayed on your synthesizer from 2.0 GHz to 6.395 GHz. Use both the cursor control key’s Ù and Ú pads and the rotary data knob to make the value changes. When you are finished, your menu display should look like the example below.

To close the open parameter when you are finished editing , press Edit F1 or make another menu selec tion.

681XXC OM 3-19

LOCAL (FRONT ENTERING

PANEL) OPERATION DATA

Clear Entry

Key

CLEAR ENTRY

Back

Space

Key

BACK

SPACE

Terminator

Keys

GHz

Sec

dBm

MHz

kHz

STEPS

ADRS

Entering a New Value

To change the current value of a parameter by en

tering a new value for the parameter, use the data entry keypad and termination keys.

As soon as you press one of the keys on the data en try keypad, the current parameter display clears for entry of a new value. Enter the new value for the parameter, then press the appropriate terminator key to store it in memory. If the entered value is out side the allowable range of the open parameter, the entry is not accepted and the previous value for the parameter is displayed.

NOTE

A frequency entry may be terminated in GHz, MHz, kHz, or Hz; however, it is al

ways displayed on the data display in GHz. Atime entry may be terminated in Sec, ms, ms, or ns; however it is always displayed on the data display in Sec.

If you make an error during data entry, either (1) press BACK SPACE to delete the entry one character at a time starting from the last character entered, or (2) delete the entire entry by pressing

CLEAR ENTRY . Then, reenter the correct value.

Now, try entering a new value for the CW frequency displayed on your synthesizer using the data entry keypad and termination keys.

To close the open parameter when you are finished entering data, press Edit F1 or make another menu selection.

3-20 681XXC OM

LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION

3-7 CW FREQUENCY

OPERATION

NOTE

When thesignal generator is reset, itautomaticallycomes upoperating in the CW frequency mode.

One of the signal generator’s major functions is to produce discrete CW frequencies across the frequency range of the instrument. The following paragraphs describe how to place the 681XXC in the CW frequency mode, select a CW frequency and power level for output, and activate the CW ramp. Use the CW Frequency Mode menu map (Chapter 4, Figure 4-2) to follow the menu sequences.

Selecting CW Mode

To place the 681XXC in the CW frequency mode, press the main menu key

CW/SWEEP

SELECT

At the resulting menu display, press CW . The CW Menu (below) is displayed.

This menu lets you perform the following:

Select a CW frequency for output.

Copy the current frequency and power infor mation to the current list index. (Refer to page 3-41 for the list sweep frequency mode operat ing instructions.)

Go to the master-slave menu. (Refer to Chap ter 7, paragraph 7-2 for Master-Slave mode op erating instructions.)

Select an output power level for the CW fre quency.

Go to the CW ramp menu (set the ramp sweep time and turn the CW ramp on/off).

681XXC OM 3-21

LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION

Selecting a CW Frequency

There are several ways to select a CW frequency for output. You can (1) edit the current frequency, (2) enter a new frequency, or (3) select one of the 20 pre set frequency parameters.

Editing the Current Frequency

Press Edit F1 to open the frequency parameter, then edit the current CW frequency using the cursor control key or the rotary data knob. To close the open frequency parameter, press Edit F1 or make another menu selection.

Entering a New Frequency

Press Edit F1 to open the frequency parameter, then enter the new CW frequency using the keypad and appropriate terminator key. To close the open frequency parameter, press Edit F1 or make an other menu selection.

Selecting a Preset Frequency

To select one of the preset frequencies for output, press the main menu key

FREQUENCY

CONTROL

The CW Frequency Control Menu (below) is displayed.

This menu lets youperform the following:

Select preset frequencies F0, F1, F2, M1,orM2 for output.

Go to the frequency list menu (to tag, edit,or output a frequency from the list).

Go to the tagged frequencies menu (select a tagged frequency for output).

3-22 681XXC OM

LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION

Frequency List–To go to the Frequency List Menu (below), press Freqs List . This menu lets you tag, edit, or output a frequency from the list.

Use the cursor control key to select a frequency from the frequency list. The selected frequency is high lighted in reverse video and displayed in full below the frequency list.

Press Tag to mark a selected frequency (place an F in front of it). If the frequency is already tagged, pressing Tag will untag it (remove the F). Tagging selected frequencies lets you quickly switch between them using the scan keys of the Tagged Frequencies menu.

Press Edit to edit the selected frequency or enter a new frequency.

Press Output Freq to output the selected frequency. This frequency is output until you select another frequency from the list and press Output Freq .On the frequency list, the output frequency selection is marked by a black square or, if tagged, an F high lighted in reverse video.

Return to the CW Frequency Control Menu display by pressing Previous Menu .

681XXC OM 3-23

LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION

Scanning Tagged Frequencies–Togotothe Tagged Frequencies Menu (below) from the CW Fre quency Control menu, press Tag Freq Menu .

This menu lets you select the tagged frequencies for output using the Scan Up and Scan Dn keys.

Return to the CW Frequency Control Menu display by pressing Previous Menu .

Selecting a Power Level

While in the CW frequency mode, you can edit the current CW frequency output power level or enter a new output power level.

Editing the Current Power Level

Press Edit L1 to open the power level parameter, then edit the current power level using the cursor control key or rotary data knob. To close the open power level parameter, press Edit L1 or make another menu selection.

Entering a New Power Level

Press Edit L1 to open the power level parameter, then enter the new power level using the keypad and appropriate terminator key. To close the open power level parameter, press Edit L1 or make an other menu selection.

NOTE

You can also select any of the preset power levels or a power level sweep for a CW frequency. For instructions, refer to paragraphs 3-9 (Fixed Power Level Op eration) and 3-10 (Power Level Sweep Operation).

3-24 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

CW Ramp When active, the signal generator’s CW ramp pro

vides a repetitive 0V to 10V ramp output to the rear panel HORIZ OUT BNC connector and AUX I/O con nector. The CW ramp is used to drive a scalar ana lyzer display.

To go to the CW Ramp Menu (below) from the CW menu, press CW Ramp Menu .

This menu lets you set the ramp speed and turn the CW ramp on/off.

To set ramp speed, press Sweep Time . The sweep time parameter opens for editing. Edit the current sweep time using the cursor control key or rotary data knob or enter a new sweep time using the key pad and appropriate termination key. The sweep time entered must be in the range of 30 ms to 99 sec. To close the open sweep time parameter when you are done, press Sweep Time or make an other menu selection.

Press CW Ramp to turn the CW ramp on. While the CW ramp is on, the message pears on the right side of frequency title bar on all CW menus.

Press Previous Menu to return to the CW Menu display.

CW Ramp ap

681XXC OM 3-25

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

3-8 SWEEP FREQUENCY

OPERATION

The signal generator can generate broad (full range) and narrow band sweeps across the frequency range of the instrument. The 681XXC has four sweep frequency modes—analog sweep, step sweep, manual sweep, and list sweep. Descriptions and operating instructions for the analog, step, and manual sweep frequency modes begin on this page. List sweep frequency mode descriptions and operating instructions be gin on page 3-41. Use the Analog Sweep, Step Sweep, Manual Sweep, and List Sweep Frequency Mode menu maps (Chapter 4, Figures 4-3, 4-4, 4-5, and 4-6) to follow the menu sequences.

Analog Sweep Mode

In analog sweep frequency mode, the signal genera tor’s output frequency is swept between selected start and stop frequencies. Sweep width can be set from 1 MHz to the full frequency range of the signal generator. Sweep time can be set for any time in the range of 30 ms to 99 sec. The lower frequency limit for analog sweeps is 10 MHz.

When the sweep width of the analog sweep is >100 MHz, the sweep is phase-lock corrected at both the start and stop frequencies and at each bandswitch point. When the sweep width is £100 MHz, only the center frequency of the sweep is phase-lock corrected.

Selecting Analog Sweep Mode

To place the 681XXC in analog sweep frequency mode, press the main menu key

CW/SWEEP

SELECT

At the resulting menu display, press Analog . The Analog Sweep Menu (below) is then displayed.

3-26 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

This menu lets you perform the following:

Select a sweep range (edit the sweep start and

stop frequency parameters). Go to the sweep ramp menu (set the sweep

time and select a sweep trigger). Select an output power level for the sweep.

Go to the alternate sweep menu.

Setting Sweep Time

To go to the Analog Sweep Ramp menu (below) from the Analog Sweep menu, press Sweep Ramp .

This menu lets you set the sweep time and go to the trigger menu.

To open the sweep time parameter for editing, press

Sweep Time . Edit the current sweep time using the cursor control key or the rotary data knob or enter a new sweep time using the key pad and appropriate termination key. To close the open sweep time parameter once you have set the desired time, press

Sweep Time or make another menu selection. To go to the Analog Sweep Trigger menu from this

menu, press Trigger Menu . Sweep trigger is de scribed on the next page.

Press Previous Menu to return to the Analog Sweep Menu display.

681XXC OM 3-27

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Selecting a Sweep Trigger

There are three modes of sweep triggering provided for analog sweep and step sweep—automatic, exter nal, and single. The sweep trigger is selectable from the trigger menu. The following is a description of each mode.

Auto (Automatic)–The sweep continually

sweeps from its start frequency to its stop fre quency with optimal retrace time. External–The sweep recurs when triggered by

an external TTL-compatible clock pulse to the rear panel AUX I/O connector. Single–A single sweep starts when the trigger

key is pressed. If a sweep is in progress when the key is pressed, it aborts and resets.

To go to the Sweep Trigger Menu (below) from the Analog Sweep Ramp menu, press Trigger Menu .

To select a sweep trigger mode, press its menu softkey. Amessage showing the sweep trigger mode se lected appears on the right side of frequency title bar. When you are finished, press Previous Menu to return to the Analog Sweep Ramp Menu display.

If you select the single sweep trigger mode, the menu display adds the menu soft-key Trig . Press ing Trig starts a single sweep. If a single sweep is in progress, pressing Trig causes the sweep to abort and reset.

3-28 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Step Sweep Mode

Selecting Step Sweep Mode

In step sweep frequency mode, the output frequency changes in discrete, synthesized steps between selected start and stop frequencies. Step sweeps can be from a low frequency to a high frequency or from a high frequency to a low frequency. Step sweeps can be selected to be linear or logarithmic. Sweep width can be set from 1 kHz (0.1 Hz with Option 11) to the full frequency range of the instrument.

The step size or number of steps between the start and stop frequencies, the dwell time-per-step, the sweep time, and the type of step sweep (linear or logarithmic) and sweep trigger are controllable from step sweep menus.

To place the 681XXC in step sweep frequency mode, press the main menu key

CW/SWEEP

SELECT

At the resulting menu display, press Step . The Step Sweep Menu (below) is then displayed.

This menu lets you perform the following:

Select a sweep range (edit the sweep start and stop frequency parameters).

Go to the sweep ramp menu (set the dwell time-per-step, the step size or number of steps, set the sweep time, select log or linear sweep, and select a sweep trigger).

Select an output power level for the sweep.

Go to the alternate sweep menu.

Setting Step Size, Dwell Time, and Sweep Time

In linear step sweep, the sweep is linearly incre mented (or decremented) by the step size from the start frequency to the stop frequency. There are two ways to set the size of each step of the linear step sweep—set the step size or set the number of steps.

681XXC OM 3-29

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

The step size range is 1 kHz (0.1 Hz with Option 11) to the full frequency range of the signal generator; the number of steps range is 1 to 10,000. If the step size does not divide into the frequency range, the last step is truncated.

In logarithmic step sweep, step size increases loga rithmically with frequency and is determined by a logarithmic curve fitted between the sweep start and stop frequencies and the number of steps. The number of steps range is 1 to 10,000.

The dwell time-per-step of the step sweep can be set for any time in the range of 1 ms to 99 sec. When dwell-time-per-step and step size or number of steps is set, the sweep time equals dwell-time-per-step times the number of steps plus the total phaselocking time for all step frequencies. If sweep time is set, then dwell-time-per-step is the result of the sweep time divided by the number of steps. In this case, the resultant minimum dwell time must be ³10 ms to allow for phase-locking of each step frequency. The sweep time of the step sweep can be set for any time in the range of 20 ms to 99 sec.

To go to the Step Sweep Ramp menu (below) from the Step Sweep menu, press Sweep Ramp .

This menu lets you set the dwell time, the step size

RANGE

This error message is displayed when (1) the stepsizevalueentered is greater than the sweeprange, (2) the number ofsteps entered results in a step size of less than 1 kHz (0.1 Hz with Option 11), or (3) the sweep time entered divided by the numberof steps entered results in a dwelltimeof<10 ms. Enteringvalid values will clear the error.

in linear step sweep, the number of steps, and go to the additional step sweep ramp menu (to set the sweep time, select log or linear sweep, and select a sweep trigger).

Press Dwell Time to open the dwell time-per-step parameter.

Press Step Size to open the step size parameter. Press Num of Steps to open the number of steps

parameter.

3-30 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Open the parameter you wish to change, then edit the current value using the cursor control key or the rotary data knob or enter a new value using the key pad and appropriate termination key. When you have finished setting the open parameter, close it by pressing its menu soft-key or make another menu selection.

Press More to go to the Additional Step Sweep Ramp menu.

Press Previous Menu to return to the Step Sweep Menu display.

Additional Step Sweep Ramp Menu

When you press More, the Additional Step Sweep Ramp Menu (below) is displayed.

This menu lets you set the sweep time, select logarithmic or linear step sweep, and go to the trigger menu.

To open the sweep time parameter for editing, press

Sweep Time . Edit the current sweep time using the cursor control key or the rotary data knob or enter a new sweep time using the keypad and appropriate terminator key. To close the open sweep time pa rameter once you have set the desired time, press

Sweep Time or make another menu selection. Press Log/Linear to select logarithmic or linear step

sweep operation. The soft-key label is highlighted (in reverse video) to reflect your selection.

Press Trigger Menu to go to the Step Sweep Trigger menu. The trigger menu lets you select a sweep trig ger (previously described on page 3-28).

Press Previous Menu to return to the Step Sweep Ramp Menu display.

681XXC OM 3-31

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Manual Sweep Mode

Selecting Manual Sweep Mode

In manual sweep frequency mode, the output fre quency can be manually tuned in phase-locked steps between the selected start and stop frequencies us ing the rotary data knob. As the knob is turned, the current output frequency is displayed on the data display as Fm. The step size or number of steps be tween the start and stop frequencies are controlla ble from the manual sweep menu. The step size range is 1 kHz (0.1 Hz with Option 11) to the full frequency range of the instrument; the number of steps range is 1 to 10,000.

To place the 681XXC in manual sweep frequency mode, press the main menu key

CW/SWEEP

SELECT

At the resulting menu display, press Manual . The Manual Sweep Menu (below) is then displayed.

This menu lets you perform the following:

Select a sweep range (edit the start and stop frequency parameters).

Set the step size or number of steps (previously described on page 3-30).

3-32 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Selecting a Sweep Range

Selecting a sweep range involves choosing a start and a stop frequency for the frequency sweep. The sweep range selection process is identical for the analog sweep, step sweep, and manual sweep fre quency modes. You can select a frequency sweep range as follows:

Editing the current start and stop frequency

parameter values. Entering new start and stop frequency pa

rameter values. Selecting one of the preset sweep range pa

rameters (F1-F2, F3-F4, F5-dF,orF6-dF).

Editing the Current Start / Stop Frequencies

To edit the current sweep range, open either the start or stop frequency parameter. In the display above, Edit F1 opens the start frequency parameter; Edit F2 opens the stop frequency parameter.

RANGE

This error message is displayed when (1) the analog sweepstartfre quency entered is greater than the stop frequency, or (2) the dF value entered results in a sweep outside the range of the 681XXC. Entering valid values will clear the error.

Edit the open frequency parameter using the cursor control key or the rotary data knob. When you are finished, close the open parameter by pressing its menu edit soft-key or by making another menu se lection.

Entering New Start / Stop Frequencies

To enter a new frequency sweep range, open either the start or stop frequency parameter (press Edit F1 or Edit F2 ).

Enter a new frequency using the keypad and appro priate terminator key. When you are finished, close the open parameter by pressing its menu edit softkey or by making another menu selection.

681XXC OM 3-33

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Selecting a Preset Sweep Range

There are four preset sweep range parameters, se lectable in the analog sweep, step sweep, and man ual sweep frequency modes. The following is a description of each preset sweep range.

F1-F2–provides a frequency sweep between the

start frequency, F1, and the stop frequency, F2. F3-F4–provides a frequency sweep between the

start frequency, F3, and the stop frequency, F4. F5-dF–provides a symmetrical frequency

sweep about the center frequency, F5. The sweep width is determined by the dF frequency parameter. F6-dF–provides a symmetrical frequency

sweep about the center frequency, F6. The sweep width is determined by the dF frequency parameter.

To select one of the preset sweep ranges from any sweep frequency mode menu, press the main menu key

FREQUENCY

CONTROL

The Sweep Frequency Control Menu (below) is displayed.

This menu lets you perform the following:

Select a full range sweep (Fmin–Fmax) or one of the preset sweep ranges for the sweep fre

quency mode.

Select the frequency parameters for each pre set sweep range.

Select an output power level for the sweep.

Go to the marker list menu (analog and step sweep frequency modes only).

3-34 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Selecting a Power Level

Setting a Preset Sweep Range–At the menu, se lect the sweep range (F1-F2, F3-F4, F5-dF,orF6-dF) that you wish to set. The menu then displays the current frequency parameters for the selected sweep range. Now, use the menu edit soft-keys to open the frequency parameters for editing.

Edit the current frequency parameters or enter new frequency parameter values for the sweep range. To close the open frequency parameter when you are finished, press its menu edit soft-key or make an other menu selection.

You can set all the preset sweep ranges in this man ner.

While in a sweep frequency mode, you can edit the current output power level or enter a new output power level for the frequency sweep.

Editing the Current Power Level

Entering a New Power Level

NOTE

You can also select any of the preset power levels for a frequency sweep or a power level step for analog and step sweeps. For instructions, refer to para graphs 3-9 (Fixed Power Level Operation) and 3-10 (Power Level Sweep Operation).

681XXC OM 3-35

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Frequency Markers

The signal generator provides up to 20 independent, pre-settable markers, F0-F9 and M0-M9, that can be used in the analog and step sweep frequency modes for precise frequency identification. Marker frequency accuracy is the same as sweep frequency accuracy. The markers are visible on a CRT display.

The 681XXC generates two types of markers.

Video Marker–produces a pulse on a CRT

display at each marker frequency. The video marker is either a +5V or a –5V pulse at the rear panel. The polarity of the video marker pulse is selectable from a system configuration menu. Intensity Marker–produces an intensified

dot on a CRT display at each marker fre quency. They are obtained from a momentary dwell during the sweep at each marker frequency. Intensity markers are only available in the analog sweep frequency mode at sweep times of <1 second.

To output markers during a sweep you must first select (tag) the marker frequencies from the Marker List menu, then turn on the marker output. To go to the Marker List menu from an analog or step sweep frequency menu, press

FREQUENCY

CONTROL

The Sweep Frequency Control Menu (below) is dis played.

To go to the Marker List menu from this menu, press Marker List . The Marker List Menu (next page) is displayed. This menu lets you tag or edit marker list frequencies and turn the markers on/off.

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LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Use the cursor control key to select a frequency parameter from the marker list. The selected fre quency parameter is highlighted in reverse video and displayed in full below the marker list.

Editing a Marker List Frequency

If you want to change a selected marker list fre quency parameter’s value, press Edit to open the frequency parameter, then edit the current fre quency or enter a new frequency.

Tagging a Marker List Frequency

Only frequencies on the marker list that have been tagged can be output as markers during a sweep. Press Tag to tag a selected frequency parameter (place an m in front of it). If a frequency parameter is already tagged, pressing Tag will untag it (remove the m).

Activating Markers

The soft-keys Video Markers and Intensity Markers toggle the markers on and off.

Video Markers–To output the tagged marker fre quencies as video markers during an analog or step sweep, press Video Markers . Video markers will be displayed on the CRT for all tagged marker frequen cies that are within the sweep frequency range.

Intensity Markers–(only available in analog sweep frequency mode) To output the tagged marker fre

quencies as intensity markers during an analog sweep, press Intensity Markers . Intensity markers will be displayed on the CRT for all tagged marker frequencies that are within the analog sweep fre quency range.

Press Previous Menu to return to the Sweep Fre quency Control Menu display.

681XXC OM 3-37

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Selecting Alternate Sweep Mode

In alternate sweep frequency mode, the signal gen erator’s output frequency sweeps alternately be tween any two sweep ranges in analog sweep or any two sweep ranges in step sweep. The process of se lecting and activating the alternate sweep is identi cal for both analog and step sweep frequency modes.

To select the alternate sweep mode for analog sweeps, start with the Analog Sweep Menu display; to select the alternate sweep mode for step sweeps, start with the Step Sweep Menu display (below).

To go to the Alternate Sweep Menu (below) from the Step Sweep menu, press Alt Swp Menu .

This menu lets you perform the following:

Turn the alternate sweep mode on/off.

Go to the alternate range menu to select a sweep range for the alternate sweep.

Go to the alternate level menu to select a power level for the alternate sweep.

Activating the Alternate Sweep

The Alternate Sweep menu soft-key Alt Sweep tog gles the alternate sweep mode on and off.

Press Alt Sweep to turn on the alternate sweep mode. Notice that the Alternate Sweep menu (on the following page) changes to show that the alter nate sweep is now active.

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LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Now, press Previous Menu to return to the Step Sweep Menu display (or the Analog Sweep Menu display if operating in analog sweep frequency mode).

Notice the changes to the Step Sweep Menu display (below). These changes indicate that the alternate sweep frequency mode is active.

Now, press Alt Swp Menu to return to the Alternate Sweep Menu display.

Selecting an Alternate Sweep Range

To go to the Alternate Range Menu (below) from the Alternate Sweep menu, press Alt Range .

Select the alternate sweep range (Full, F1-F2, F3-F4, F5-dF,orF6-dF). The menu then displays the cur rent frequency parameters for the selected sweep range. If you wish to change a frequency parameter, use the menu edit soft-key to open the parameter, then edit it.

681XXC OM 3-39

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

When you are done selecting the alternate sweep range, press Previous Menu to return to the Alter nate Sweep Menu display.

Selecting an Alternate Sweep Power Level

To go to the Alternate Level Menu (below) from the Alternate Sweep menu, press Alt Level .

Select the power level for the alternate sweep range (L0, L1, L2, L3, or L4). The menu then displays the current level parameter for the selected power level. If you wish to change the level, use the menu edit soft-key to open the parameter, then edit it.

A menu edit soft-key is also provided to let you change the power level of the main sweep.

CAUTION

Performing alternate sweeps using power levels that cross step attenuator switch points can cause excessive wear on the switches and reduce the life expectancy of the step attenuator.

When you are done selecting the power level for the alternate sweep range and editing the power level of the main sweep, press Previous Menu to return to the Alternate Sweep Menu display.

3-40 681XXC OM

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

List Sweep Mode

In list sweep frequency mode, the output is a step sweep of up to 2000 phase-locked, non-sequential frequencies. Each frequency can have a different power level setting. The list index (0 thru 1999) identifies each frequency/power level set in the list. The list sweep is defined by a list start index and a list stop index.

There are four modes of sweep triggering in list sweep—automatic, external, single, and manual. When automatic, external, or single trigger mode is selected, the output sweeps between the specified list start and stop indexes, dwelling at each list in dex for the specified dwell time. When manual trig ger mode is selected, the list start index, list stop index, and dwell time parameter are not used. In stead, the list index is incremented or decremented by using the front panel cursor control key. In man ual trigger mode, the list index can also be incremented by using an external trigger input. Each TTL trigger increments the list index by one.

After a reset, the list sweep defaults to manual trigger mode. The data display shows the trigger mode, the list index, current frequency, and current power level. The list index specifies the current location within the list. The current frequency is preceded by the text “Fr”. The current power level is preceded by the text “Lv”. When automatic, external, or single trigger mode is selected, the data display changes to show the trigger mode and list sweep start and stop index values only.

The list of up to 2000 frequency/power level sets is stored in non-volatile RAM to preserve any settings after the instrument is powered off. The list is not stored with the other setup information in the in strument. After a master reset, the list is reset to its default state of 2000 index entries of 5 GHz at 0 dBm.

681XXC OM 3-41

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Selecting List Sweep Mode

To place the 681XXC in list sweep frequency mode, press the main menu key

CW/SWEEP

SELECT

At the reulting menu display, press List . The List Sweep Menu (below) is displayed.

This menu lets you perform the following:

Go to the Edit List menus (edit list index fre-

quency and power level parameters and insert and delete list index entries).

Edit the list index parameter.

Calculate all list index frequency and power level settings.

Go to the Sweep menu (set sweep start index, stop index, and dwell time and select a sweep trigger).

Editing the List Index

Press List Index to open the list index parameter for editing. Edit the current list index value using the cursor control key or rotary data knob or enter a new value using the key pad and any terminator key. When you have finished setting the open pa rameter, close it by pressing List Index or by mak ing another menu selection.

The List Index soft-key is not the only way to change the list index. In the list sweep mode with manual trigger selected, each time the Ù or Ú pad of the cursor control key is pressed the list index incre ments or decrements by one. The List Index soft-key is used if a larger change in the list index is desired. The only time the cursor control key will not change the list index is when a different parameter, such as frequency, power level,etc., is open. The cursor con trol key will then change the value of the open parameter. Once the open parameter is closed, the cursor control key will again change the list index.

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LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Performing List Calculations

The PreCalc List soft-key initiates a process that examines every index in the list and performs all the calculations necessary to set the frequency and power levels. The soft-key does not have to be pressed every time the list changes. The instrument will perform the calculations to set the frequency and power levels as it performs the initial list sweep. This causes the initial list sweep to take longer than each subsequent sweep. Using the

PreCalc List soft-key lets the initial list sweep be as fast as each subsequent sweep. The calculations are stored in volatile RAM and are lost at instrument power-off.

Press PreCalc List to perform list calculations. The soft-key image depresses to show that calculations are in progress. When the calculations are com pleted, the soft-key returns to normal appearance.

Editing the List

List editing consists of editing list index frequency and power level parameters and inserting and deleting list index entries.

To go to the Edit List Menu (below) from the List Sweep menu, press Edit List .

This menu lets you perform the following:

Go to the List Frequency Edit menu (edit list index frequency parameters).

Go to the List Power Edit menu (edit list index power level parameters).

Go to the Additional Edit List menu (insert and delete list index entries).

681XXC OM 3-43

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

List Frequency Edit–to go to the List Frequency Edit Menu (below), press Edit Freq . This menu lets you scroll through the list frequencies and edit se lected frequencies.

The menu displays a total of 20 frequencies. The in dex range of the displayed frequencies is shown at the top of the list. Use the cursor control key to se lect a frequency from the list. The selected frequency is highlighted in reverse video and displayed in full below the frequency list.

Press Edit to edit the highlighted frequency or enter a new frequency.

Press Page Up to scroll the displayed frequencies to the next 20 in the list. Press Page Down to scroll the displayed frequencies to the previous 20 in the list.

Press Previous Menu to return to the Edit List Menu display.

List Power Edit–to go to the List Power Edit Menu (below) from the Edit List menu, press

Edit Power . This menu lets you scroll through the

list power levels and edit selected power levels.

The menu displays a total of 10 power levels. Use the cursor control key to select a power level from the list. The selected power level is highlighted in reverse video and displayed in full below the power level list.

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LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Press Edit to edit the highlighted power level or en ter a new power level.

Press Page Up to scroll the displayed power levels to the next 10 in the list. Press Page Down to scroll the displayed power levels to the previous 10 in the list.

Press Previous Menu to return to the Edit List Menu display.

Additional Edit List Menu

At the Edit List menu, press More to go to the Ad ditional Edit List Menu (below).

This menu lets you insert and delete entries from the list.

Press Insert Entry to insert the default frequency (5 GHz) and power level (0 dBm) at the current list index.

NOTE

Because the list size is fixed, inserting a new index will cause the last index to be lost. Whatever frequency and power level are at list index 1999 will be deleted and cannot be recovered.

Press Delete Entry to delete the current list index.

NOTE

Delete entry cannot be undone. Once a list index is deleted, the only recovery is to re-enter the deleted frequency and power level.

Press Previous Menu to return to the main Edit List Menu display.

681XXC OM 3-45

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Copying Data from the CW Menu

An easy method of entering frequency and power level information into the current list index is to copy the data from the CW menu.

Fisrt, go to the main List Sweep menu and press the

List Index soft-key to open the list index parameter. Then, select the list index that you want the data to be added to.

Next, press the CW soft-key. The CW Menu (below) is displayed.

Selecting a List Sweep Range

Use the Edit F1 and Edit L1 soft-keys to set the frequency and power level to the values you wish to enter into the current list index.

Press the Copy to List soft-key to copy the data to the current list index.

Once the frequency and power level information has been entered into the current list index, the list in dex is incremented by one.

Selecting a sweep range involves choosing a start index and stop index for the list sweep.

To go to the Sweep Menu (below) from the main List Sweep menu, press Sweep Menu .

This menu lets you select a list sweep range, set the dwell-time-per-step, and go to the trigger menu.

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LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

Press Start Index to open the list sweep start index parameter.

Press Stop Index to open the list sweep stop index parameter.

Press Dwell Time to open the dwell-time-per-step parameter.

Open the parameter you wish to change, then edit the current value using the cursor control key or ro tary data knob or enter a new value using the key pad and appropriate terminator key. When you have finished setting the open parameter, close it by pressing its menu soft-key or by making another menu selection.

To go to the List Sweep Trigger menu from this menu, press Trigger . The trigger menu lets you se lect a list sweep trigger.

Press Previous Menu to return to the main List Sweep Menu display.

Selecting a List Sweep Trigger

There are four modes of sweep triggering in list sweep frequency mode, each selectable from the trigger menu. The following is a description of each mode

Auto (Automatic)–The output sweeps between the specified list start and stop indexes, dwelling at each list index for the specified dwell time.

External–The output sweep recurs when trig gered by an external TTL-compatible clock pulse to the rear panel AUX I/O connector.

Single (Trig)–A single output sweep starts when the trigger key is pressed. If a sweep is in progress when the key is pressed, it aborts and resets.

Manual–(list sweep default trigger mode) The list index is incremented or decremented by using the front panel cursor control key. The list index can also be incremented using an ex ternal trigger input. Each trigger increments the list index by one.

681XXC OM 3-47

LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION

To go to the List Sweep Trigger Menu (below) from the Sweep menu, press Trigger .

To select a sweep trigger mode, press its menu softkey. Amessage showing the trigger mode selected appears on the right side of the frequency title bar. When you are finished, press Previous Menu to return to the Sweep Menu display.

If you select the single trigger mode, the Single soft-key is replaced by the Trig soft-key. Pressing

Trig starts a single sweep. If a single sweep is in progress, pressing Trig causes the sweep to abort and reset.

NOTE

With Auto trigger selected and the dwelltime-per-step set to a small value, display updating slows down. This ensures that sweep speed is not adversely affected. Be cause of this potential display update slow down, when leaving list sweep mode with auto trigger selected for another mode, Auto trigger is automatically turned off and Manual trigger is selected. Thus, when list sweep mode is entered, the display updating will be back to nor mal speed.

3-48 681XXC OM

LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION

3-9 FIXED POWER LEVEL

OPERATION

The signal generator provides leveled output power over a maximum range of up to 33 dB (up to 149 dB with Option 2) for CW and sweep frequency operations. Units with Option 15A provide leveled output power over a maximum range of up to 27 dB (up to 141 dB with Op tion 2). The following paragraphs describe how to place the signal gen erator in fixed (non-swept) power level mode, select a power level for output, select logarithmic or linear units, and activate level offset. Use the Fixed (Non-Swept) Power Level Mode menu map (Chapter 4, Fig ure 4-7) to follow the menu sequences.

Selecting Fixed Power Level Mode

To place the 681XXC in a fixed power level mode from a CW or sweep (analog, step, or manual) fre quency menu, press the main menu key

LEVEL/ALC

SELECT

At the resulting menu display, press Level . The Level Menu (below) is displayed.

This menu lets you perform the following:

Edit the power level parameter.

Edit the level offset parameter.

Turn level offset on/off.

Selecting a Power Level

There are several ways to select a power level for output. You can (1) edit the current power level, (2) enter a new power level, or (3) select one of the 10 preset power level parameters.

Editing the Current Power Level

Press Edit L1 to open the power level parameter, then edit the current power level using the cursor control key or the rotary data knob. To close the open power level parameter, press Edit L1 or make another menu selection.

Entering a New Power Level

Press Edit L1 to open the power level parameter, then enter the new power level using the keypad

681XXC OM 3-49

LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION

NOTE

When Linear power level units are selected, use thefollowing termina torkeysfor powerleveldataentries:

GHz / Sec / dBm for V MHz/ms/dBfor mV kHz / ms / STEPS for mV

and appropriate terminator key. To close the open power level parameter, press Edit L1 or make an

other menu selection.

Selecting a Preset Power Level

To select one of the preset power levels for output, press the main menu key

LEVEL

CONTROL

The Level Control menu (below) is displayed.

This menu lets you perform the following:

Select preset power levels L0, L1, L2, L3,orL4 for output.

Go to the Level List menu.

Go to the Tagged Levels menu.

Press Log/Linear to select power level units. When Log is selected, units are in dBm; when Linear is se lected, units are in mV. The soft-key label is highlighted (in reverse video) to reflect your selection.

Level List– To go to the Level List menu (below), press Level List .

This menu lets you select a power level from the list to tag, edit, or output.

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LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION

Use the cursor control key to select a power level from the level list. The selected power level is high lighted in reverse video and displayed in full below the level list.

Press Tag to mark a selected power level (place an L in front of it). If a power level is already tagged, pressing Tag will untag it (remove the L). Tagging selected power levels lets you quickly switch be tween them using the scan keys of the Tagged Lev els menu.

Press Edit to edit the selected power level or enter a new power level.

Press Output Level to output the selected level. This power level is output until you select another level from the list and press Output Level .Onthe level list, the output power level selection is marked by a black square or, if tagged, an L highlighted in reverse video.

When you are finished , press Previous Menu to return to the Level Control Menu display.

Scanning Tagged Levels–To go to the Tagged Levels menu (shown below) from the Level Control menu, press Tag Lvl Menu .

This menu lets you select the tagged power levels for output using the Scan Up and Scan Dn keys.

Return to the Level Control Menu display by press ing Previous Menu .

681XXC OM 3-51

LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION

Level Offset Level offset lets you compensate for a device on the

signal generator’s output that alters the RF output power level at the point of interest. For example, the power level at the test device may be less or more than the displayed power level because of the loss through an external transmission line or the gain of an amplifier located between the 681XXC RF output and the test device. Using the level offset function, you can apply a constant to the displayed power level that compensates for this loss or gain. The dis played power level will then reflect the actual power level at the test device.

To enter an offset value and apply it to the displayed power level, go to the Level Menu. Then press

Edit Offset . As shown in the following menu, this opens the offset parameter for editing.

OFFSET

When Offset is selected ON, this status message is displayed on all menu displays toremind the opera tor that a constant (offset)has been applied to the displayed power level.

Edit the current offset value using the cursor control key or rotary data knob or enter a new offset value using the keypad and appropriate terminator key. To close the open offset parameter when you are done, press Edit Offset or make another menu selec tion.

Press Offset to apply the offset to the displayed

power level. In this example, a+2.00 dB offset is ap plied to L1. L1 then displays a power level of +2.00 dBm.

3-52 681XXC OM

LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

3-10 POWER LEVEL SWEEP

OPERATION

The signal generator provides leveled output power sweeps at CW fre quencies and in conjunction with frequency sweeps (analog and step). Power level sweeps can be from a high level to a low level or vice versa. Power level sweeps can be selected to be linear or logarithmic. The following paragraphs provide descriptions and operating instruc tions for the CW power sweep mode and the sweep frequency/ step power modes. Use the CW Power Sweep Mode and Sweep Frequency/ Step Power Mode menu maps (Chapter 4, Figures 4-8 and 4-9) to fol low the menu sequences.

CAUTION

Performing power level sweeps that cross step attenuator switch points can cause excessive wear on the switches and reduce the life expectancy of the step attenuator.

Selecting CW Power Sweep Mode

In the CW power sweep mode, output power steps between any two power levels at a single CW frequency. Available menus let you set or select the sweep range, the step size, the dwell-time-per-step, and the type of power sweep (linear or logarithmic) and sweep trigger.

To place the 681XXC in a CW power sweep mode from a CW frequency menu, press the main menu key

LEVEL/ALC

SELECT

At the resulting menu display, press Lvl Swp . The CW Level Sweep Menu (below) is displayed.

This menu lets you perform the following:

Select a power level sweep range (edit the sweep start and stop power level parameters).

Go to the sweep ramp menu (set the dwelltime-per-step, the step size or number of steps, and select a sweep trigger).

681XXC OM 3-53

LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

Setting CW Power Sweep Step Size and Dwell Time

There are two ways to set the size of each step of the CW power sweep—set the step size or set the number of steps. The step size range is 0.01 dB (Log) or 0.001 mV (Linear) to the full power range of the instrument; the number of steps range is 1 to 10,000. The dwell-time-per-step of the CW power sweep can be set for any time in the range of 1 ms to 99 sec. If the sweep crosses a step attenuator set ting, there will be a sweep dwell of approximately 20 ms to allow setting of the step attenuator. The step size and dwell-time-per-step are set from the CW Level Sweep Ramp menu (below).

To go to the CW Level Sweep Ramp Menu from the CW Level Sweep menu, press Sweep Ramp .

RANGE

This error message is displayed when (1) the stepsizevalueentered is greater than the level sweep range or (2)the number ofsteps en tered results in a step size of less than 0.01 dB (Log) or 0.001 mV (Linear). Entering a valid step size will clear the error.

This menu lets you set the dwell time, the step size, the number of steps, and go to the trigger menu.

Press Dwell Time to open the dwell-time-per-step parameter.

Press Step Size to open the step size parameter. Press Num of Steps to open the number of steps

parameter.

Open the parameter you wish to change, then edit

the current value using the cursor control key or ro tary data knob or enter a new value using the key pad and appropriate termination key. When you have finished setting the open parameter, close it by pressing its menu soft-key or by making another menu selection.

To go to the CW Level Sweep Trigger menu from this menu, press Trigger Menu . The trigger menu is described on the following page.

Press Previous Menu to return to the CW Level Sweep Menu display.

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LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

Selecting a CW Power Sweep Trigger

There are three modes of triggering provided for the CW power sweep—automatic, external, and single. The sweep trigger is selectable from the CW Level Sweep Trigger menu. The following is a description of each trigger mode.

Auto (Automatic)–The CW power sweep con

tinually sweeps from its start power level to its stop power level with optimal retrace time. External–The CW power sweep recurs when

triggered by an external TTL-compatible clock pulse to the rear panel AUX I/O connector. Single–A single CW power sweep starts when

the trigger key is pressed. If a sweep is in prog ress when the key is pressed, it aborts and re sets.

To go to the CW Level Sweep Trigger Menu (below) from the CW Level Sweep Ramp menu, press

Trigger Menu .

To select a CW power sweep trigger mode, press its menu soft-key. A message showing the CW power sweep trigger mode selected appears on the right side of the level mode title bar .

If you select the single sweep trigger mode, the menu display changes, adding the menu soft-key labeled Trig . Pressing Trig starts a single CW power sweep. If a single CW power sweep is in prog ress, pressing Trig causes the sweep to abort and reset.

Press Previous Menu to return to the CW Level Sweep Ramp Menu display.

681XXC OM 3-55

LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

Selecting a Power Level Sweep Range

Selecting a power level sweep range consists of choosing a start and stop level for the power level sweep. The power level sweep range selection pro cess is identical for all power level sweep modes —CW power sweep, analog sweep frequency/step power, and step sweep frequency/step power. You can select a power level sweep range as follows:

Edit the current start and stop power level

parameter values. Enter new start and stop power level parame

ter values. Select one of the preset power level sweep

range parameters (L1-L2, L3-L4, L5-L6, L7-L8, or L9-L0).

NOTE

When Linear power level sweep is selected, use thefollowing termina torkeysfor powerleveldataentries:

GHz / Sec / dBm for V MHz/ms/dBfor mV kHz / ms / STEPS for mV

Editing the Current Start / Stop Power Levels

To edit the current power level sweep range, start by opening either the start or stop power level pa rameter (in the display above, Edit L1 opens the start power level parameter; Edit L2 opens the stop power level parameter).

Edit the open power level parameter using the cur sor control key or the rotary data knob. When you are finished, close the open parameter by pressing its menu edit soft-key or by making another menu selection.

Entering New Start / Stop Power Levels

To enter a new power level sweep range start by

opening either the start or stop power level parame ters (press Edit L1 or Edit L2 ).

Enter a new power level using the keypad and ap propriate terminator key. When you are finished, close the open parameter by pressing its menu edit soft-key or by making another menu selection.

3-56 681XXC OM

LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

Selecting a Preset Power Level Sweep Range

There are five preset power level sweep range pa rameters selectable in the power level sweep modes. These preset power level sweep range parameters are L1-L2, L3-L4, L5-L6, L7-L8, and L9-L0.

To select one of the preset power level sweep ranges from a Level Sweep menu, press the main menu key

LEVEL

CONTROL

The Level Sweep Control Menu (below) is displayed.

In addition to letting you select one of the preset sweep ranges for the power level sweep, this menu lets you select logarithmic or linear power level sweep and set the start and stop power level parameters for each preset sweep range.

Setting a Preset Power Level Sweep Range–At the Level Sweep Control menu, select the power level sweep range (L1-L2, L3-L4, L5-L6, L7-L8,or L9-L0) that you wish to set. The menu then displays the current power level parameters for the selected power level sweep range. Now, use the menu edit soft-keys to open the power level parameters for ed iting.

Edit the current power level parameter values or enter new power level parameter values for the power level sweep range. To close the open power level parameter when you are finished, press its menu edit soft-key or make another menu selection.

Selecting Type of Power Level Sweep–Press

Log/Linear to select logarithmic or linear power level sweep. When Log is selected, power levels are in dBm; when Linear is selected, power levels are in mV. The soft-key label is highlighted (in reverse video) to reflect your selection.

681XXC OM 3-57

LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

Selecting a Sweep Fre quency/Step Power Mode

In analog sweep frequency/step power mode or step sweep frequency/step power mode, a power level step occurs after each frequency sweep. The power level remains constant for the length of time re quired to complete each frequency sweep. Available menus let you control the type of power level sweep (linear or logarithmic), the power level sweep range, and step size.

To select an analog sweep frequency/step power mode, start with an analog sweep menu display; to select a step sweep frequency/step power mode, start with a step sweep menu display. Then press the main menu key

LEVEL/ALC

SELECT

At the resulting menu display, press Lvl Swp . The Level Sweep Menu is displayed.

This menu lets you perform the following:

Select a power level sweep range (edit the sweep start and stop power level parameters).

Go to the sweep ramp menu (set the step size or number of steps).

NOTE

To select logarithmic or linear power level sweep or to select a power level sweep range, refer to the procedures on pages 3-56 and 3-57.

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LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION

Setting Power Level Step Size

There are two ways to set the step size of the power level step that occurs after each frequency sweep —set the step size or set the number of steps. The step size range is 0.01 dB (Log) or 0.001 mV (Linear) to the full power range of the ssignal generator; the number of steps range is 1 to 10,000. The power level step size is set from the level sweep ramp menu.

To go to the Level Sweep Ramp Menu (below) from the Level Sweep menu, press Sweep Ramp .

This menu lets you set the step size and the number of steps.

Press Step Size to open the step size parameter.

RANGE

Press Num of Steps to open the number of steps parameter.

Open the parameter you wish to change, then edit

Press Previous Menu to return to the Level Sweep Menu display.

681XXC OM 3-59

LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS

3-11 LEVELING

OPERATIONS

The 681XXC generates leveled output power over a maximum range of up to 33 dB (up to 149 dB with Option 2). Instruments with Option 15A provide leveled output power over a maximum range of up to 27 dB (up to 141 dB with Option 2). An automatic level control (ALC) system controls the amplitude and power level of the RF output. The operator can select the ALC mode of operation—internal, external (detector or power meter), or fixed gain (ALC off). In addition, the sig nal generator provides (1) an ALC power slope function that provides compensation for high frequency system or cable losses, (2) a decouple function that allows decoupling of the step attenuator (if equipped) from the ALC system, and (3) a user level (flatness correction) calibra tion function that provides for calibrating out path variations with fre quency in a test setup.

The following paragraphs provide descriptions and operating instruc tions for the power leveling modes and functions. Use the Leveling Modes menu map (Chapter 4, Figure 4-10) to follow the menu se quences.

Selecting a Leveling Mode

The ALC system is a feedback control system, in which the output power is measured at a detector and compared with the expected power level. If the output and desired power levels do not equal, the ALC adjusts the power output until they do. The feedback signal can be provided by either the internal detector or an external detector or power meter. Alternatively, the output power can be set to a fixed level without using the normal feedback (ALC off). The ALC mode menu lets you make the selection of a leveling mode.

To go to the ALC Mode menu, first press the main menu key

LEVEL/ALC

SELECT

At the Level/ALC Select Menu display, press

ALC Mode . The ALC Mode Menu (below) is

displayed.

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LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS

The ALC Mode menu lets you perform the following:

Go to the leveling menu (select the ALC mode

of operation). Go to the attenuation menu (decouple the

attenuator, if equipped, from the ALC system and set the power level and attenuation). Select either the front panel or rear panel ex

ternal ALC input.

Internal Leveling

This is the normal (default) leveling mode. Output power is sensed by the internal detector in the 681XXC. The detector output signal is fed back to the ALC circuitry to adjust the output power level. Internal ALC is selected from the leveling menu.

To go to the Leveling Menu from the ALC Mode menu, press Leveling Menu . The Leveling Menu (below) is displayed.

To select internal ALC, press Internal . Pressing one of the other leveling menu soft-keys

External Detector , Power Meter ,or Fixed Gain will turn off internal leveling.

Press Previous Menu to return to the ALC Mode Menu display.

External Leveling

In external leveling, the output power from the 681XXC is detected by an external detector or power meter. The signal from the detector or power meter is returned to the ALC circuitry. The ALC adjusts the output power to keep the power level constant at the point of detection. The external ALC source in put is selected from the leveling menu.

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LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS

Before going to the Leveling Menu from the ALC Mode menu, select whether the external ALC signal is to be connected to the front- or rear-panel EXT ALC IN connector.

At the ALC Mode menu, press Ext ALC Front to se lect front panel input, or Ext ALC Rear to select rear panel input.

Now, press Leveling Menu to go to the Leveling Menu (below).

Next, select the type of external sensor you are using to detect the output power.

To select the external ALC input from an external detector, press External Detector .

To select the external ALC input from a power meter, press Power Meter .

After you have made the external ALC input con nection and selected the sensor type, press

ALC Loop . The ALC Loop Menu (below) is dis

played.

While monitoring the power level at the external de tection point, first press Ext ALC Adj , then use the cursor control key or rotary data knob to adjust the external ALC signal to obtain the set power level.

To return to the Leveling Menu, press ALC Mode then press Leveling Menu .

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At the Leveling menu, pressing either Internal or

Fixed Gain will turn off external leveling.

Press Previous Menu to return to the ALC Mode Menu display.

Fixed Gain

In the fixed gain mode, the ALC is disabled. The RF Level DAC and step attenuator (if installed) are used to control the relative power level. Power is not detected at any point, and the absolute power level is uncalibrated. Fixed gain mode is selected from the leveling menu.

Press Leveling Menu to go to the Leveling Menu.

To select fixed gain mode, press Fixed Gain . To return to normal ALC operation, press Internal . Press Previous Menu to return to the ALC Mode

Menu display.

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LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS

Attenuator Decoupling

In 681XXCs equipped with option 2 step attenua tors, the ALC and attenuator work in conjunction to provide leveled output power down to –140 dBm. In the normal (coupled) leveling mode, when the de sired power level is set, the correct combination of ALC level and attenuator setting is determined by the instrument firmware. In some applications, such as receiver sensitivity testing, it is desireable to con trol the ALC level and attenuator setting separately by decoupling the step attenuator from the ALC. The ALC mode menu lets you select attenuator decoupling.

At the ALC Mode menu, press Atten Menu . The Attenuator Menu (below) is displayed.

NOTE

The set power level may not be maintained when switching be tween attenuator coupling modes.

This menu lets you decouple the step attenuator from the ALC, set the power level, and set the attenuation in 10 dB steps.

Press Decouple to decouple the step attenuator from the ALC.

Press Edit L1 to open the power level parameter for editing. Edit the current level using the cursor con trol key or rotary data knob or enter a new value us ing the key pad and appropriate termination key. When you have finished setting the power level, press Edit L1 to close the open parameter.

To change the attenuation setting, press Incr Atten or Decr Attn . Pressing these soft-keys changes the attenuation in 10 dB steps.

Press Previous Menu to return to the ALC Mode Menu display.

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ALC Power Slope

Power Level

The ALC power slope function lets you compensate for system, cable, and waveguide variations due to changes in frequency, by linearly increasing or de creasing power output as the frequency increases. As shown in the following illustration, the power slope function provides you with the ability to set both the power slope and the pivot point. The ALC loop menu lets you activate the ALC power slope function.

Power Slope

Power Slope Pivot Point

Power at DUT With Compensation

Power at DUT Without Compensation

Frequency

To go to the ALC Loop Menu from the Level/ALC Control Menu display, press ALC Loop . The ALC Loop Menu (below) is displayed.

This menu lets you turn the power slope on or off and edit the slope value and pivot point frequency.

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LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS

Press Slope On/Off to activate the ALC power slope function.

Press Edit Pivot to open the pivot point frequency parameter for editing. Edit the current frequency

SLOPE

When Power Slope is selected ON, this status messageis displayed on all menu displays toremindthe operatorthatapowerslopecorrection has been applied to the ALC.

using the cursor control key or rotary data knob or enter a new value using the keypad and appropriate termination key. When you have finished setting the open parameter, close it by pressing Edit Pivot again or by making another menu selection.

Press Edit Slope to open the slope parameter for editing. Edit the current slope value using the cursor control key or rotary data knob or enter a new value using the key pad and the STEPS termination key. When you have finished setting the open parameter, close it by pressing Edit Slope again or by making another menu selection.

While monitoring the power level at the deviceunder-test (DUT), adjust the power slope and pivot point to level the power at the DUT.

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G P I B

User Cal (User Level Flatness Correction)

6 8 1 X X C S I G N A L G E N E R A T O R

The User Cal (user level flatness correction) func

tion lets you calibrate out path variations with frequency that are caused by external switching, amplifiers, couplers, and cables in the test setup. This is done by means of an entered power-offset table from a GPIB power meter or calculated data. When user level flatness correction is activated, the set power level is delivered at the point in the test setup where the calibration was performed. This “flattening” of the test point power level is accom

plished by summing a power-offset word (from the power-offset table) with the signal generator’s nor

mal power level DAC word at each frequency point. Up to five user level flatness correction power-offset

tables from 2 to 801 frequency points/table can be created and stored in 681XXC memory for recall. The GPIB power meters supported are the Anritsu Models ML2437A, ML2438A, and ML4803Aand the Hewlett-Packard Models 437B, 438A, and 70100A.

R F O U T P U T

I N P U T

S W I T C H M A T R I X ,

A M P L I F I E R S ,

C O U P L E R S , E T C .

F L A T N E S S C O R R E C T E D O U T P U T

D E V I C E

U N D E R

T E S T

Figure 3-4. Setup for Creating a Power-Offset Table (User Level Flatness Correction)

P O W E R

S E N S O R

G P I B

P O W E R

M E T E R

681XXC OM 3-67

Anritsu 681XXC User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

Chapter 1 General Information

Chapter 2 Installation

Chapter 3 Local (Front Panel) Operation