User’s Guide
HP 8702D
Lightwave Component Analyzer
© Copyright Hewlett-Packard
Company 1996
All Rights Reserved. Reproduction, adaptation, or translation without prior written
permission is prohibited,
except as allowed under copyright laws.
HP Part No. 08702-90041
Printed in USA
April 1997
Hewlett-Packard Company
Lightwave Operations
1400 Fountaingrove Parkway
Santa Rosa, CA 95403-1799,
USA
(707) 577-1400
Notice.
The information contained in
this document is subject to
change without notice. Companies, names, and data used
in examples herein are fictitious unless otherwise noted.
Hewlett-Packard makes no
warranty of any kind with
regard to this material, including but not limited to, the
implied warranties of merchantability and fitness for a
particular purpose. HewlettPackard shall not be liable for
errors contained herein or for
incidental or consequential
damages in connection with
the furnishing, performance,
or use of this material.
Restricted Rights Legend.
Use, duplication, or disclosure by the U.S. Government
is subject to restrictions as set
forth in subparagraph (c) (1)
(ii) of the Rights in Technical
Data and Computer Software
clause at DFARS 252.227-7013
for DOD agencies, and subparagraphs (c) (1) and (c) (2)
of the Commercial Computer
Software Restricted Rights
clause at FAR 52.227-19 for
other agencies.
War ran ty.
This Hewlett-Packard instrument product is warranted
against defects in material and
workmanship for a period of
one year from date of shipment. During the warranty
period, Hewlett-Packard Company will, at its option, either
repair or replace products
which prove to be defective.
For warranty service or repair,
this product must be
returned to a service facility
designated by Hewlett-Packard. Buyer shall prepay shipping charges to HewlettPackard and Hewlett-Packard
shall pay shipping charges to
return the product to Buyer.
However, Buyer shall pay all
shipping charges, duties, and
taxes for products returned to
Hewlett-Packard from another
country.
Hewlett-Packard warrants
that its software and firmware
designated by Hewlett-Packard for use with an instrument
will execute its programming
instructions when properly
installed on that instrument.
Hewlett-Packard does not
warrant that the operation of
the instrument, or software,
or firmware will be uninterrupted or error-free.
Limitation of Warranty.
The foregoing warranty shall
not apply to defects resulting
from improper or inadequate
maintenance by Buyer, Buyersupplied software or interfacing, unauthorized modification or misuse, operation
outside of the environmental
specifications for the product,
or improper site preparation
or maintenance.
No other warranty is
expressed or implied.
Hewlett-Packard specifically
disclaims the implied warranties of merchantability and fitness for a particular purpose.
Exclusive Remedies.
The remedies provided
herein are buyer's sole and
exclusive remedies. HewlettPackard shall not be liable for
any direct, indirect, special,
incidental, or consequential
damages, whether based on
contract, tort, or any other
legal theory.
Safety Symbols.
CAUTION
The
caution
sign denotes a
hazard. It calls attention to a
procedure which, if not correctly performed or adhered
to, could result in damage to
or destruction of the product.
Do not proceed beyond a caution sign until the indicated
conditions are fully understood and met.
WAR NIN G
The
warning
sign denotes a
hazard. It calls attention to a
procedure which, if not correctly performed or adhered
to, could result in injury or
loss of life. Do not proceed
beyond a warning sign until
the indicated conditions are
fully understood and met.
The instruction manual symbol. The product is marked with this
warning symbol when
it is necessary for the
user to refer to the
instructions in the
manual.
The laser radiation
symbol. This warning
symbol is marked on
products which have a
laser output.
The AC symbol is used
to indicate the
required nature of the
line module input
power.
The ON symbols are
|
used to mark the positions of the instrument
power line switch.
The OFF symbols
❍
are used to mark the
positions of the instrument power line
switch.
The CE mark is a registered trademark of
the European Community.
The CSA mark is a registered trademark of
the Canadian Standards Association.
This text denotes the
ISM1-A
instrument is an
Industrial Scientific
and Medical Group 1
Class A product.
Typographical Conventions.
The following conventions are
used in this book:
Key type
for keys or text
located on the keyboard or
instrument.
Softkey type
for key names that
are displayed on the instrument’s screen.
Display type
for words or
characters displayed on the
computer’s screen or instrument’s display.
User type
for words or charac-
ters that you type or enter.
Emphasis
type for words or
characters that emphasize
some point or that are used as
place holders for text that you
type.
ii
The HP 8702D—At a Glance
The HP 8702D—At a Glance
The HP 8702D performs optical and electrical transmission and reflection
measurements on lightwave systems and components. For most measurements, the HP 8702D imposes an electrical modulation signal on a lightwave
carrier and then measures the device’s response to the
signal. Typically, the HP 8702D is used with the HP 83400-series lightwave
sources and receivers.
You can perform the following transmission measurements:
• Gain and loss of an optical amplifier
• Responsivity of a photo detector
• Fault location on a fiber-optic cable
•Group delay
• Insertion phase shift
modulated
lightwave
The following reflection measurements are also possible:
• Return loss of modulated laser source
• Standing wave ratio (SWR)
• Impedance (R + jX)
Measurement accuracy—it’s up to you!
Electrical and fiber-optic connectors are easily damaged when connected to dirty or
damaged cables and accessories. The HP 8702D’s front-panel PORT 1 and PORT 2 connector is no exception. When you use improper cleaning and handling techniques, you
risk expensive instrument repairs, damaged cables, and compromised measurements.
Before you connect any cables, refer to “Cleaning Connections for Accurate Measurements” on page 1-33.
The electrical connectors are also sensitive to electrostatic discharge. Before you connect any cable to the HP 8702D, refer to “Protecting Against Electrostatic Damage” on
page 1-31.
iii
The HP 8702D—At a Glance
Several types of devices can be characterized
With the HP 8702D, you can characterize four types of devices which are categorized according to their input and output ports. They are optical devices,
lightwave sources, lightwave receivers, and electrical devices. Optical devices
include fiber-optic cables, and couplers.
The HP 8702D can make electrical measurements because it has all the capabilities of an RF/microwave network analyzer. During electrical measurements, a device’s response to an RF signal is measured.
Measurements are displayed in several formats
Depending on the measurement performed, the data can be viewed using one
of several display formats:
• Logarithmic or linear magnitude
• Smith chart
•Polar
• Standing wave ratio
•Phase
• Real or imaginary
CAUTION
Time-domain measurements
In addition to transmission and reflection measurements, the HP 8702D can
locate faults on fiber-optic cables and other devices. It locates faults or discontinuities in time or distance.
Displayed results can be saved and printed
You can get hardcopy results of your measurements by connecting a printer to
the rear-panel
PARALLEL PRINTER PORT
connector. In addition, measurement
results, instrument settings, and calibrations can be saved on a DOS-formatted
disk using the front-panel disk drive.
The HP 8702D’s
PORT 1
and
PORT 2
connectors are static sensitive. Do not touch
the center conductor of these connectors. Do not allow any static charge to
come into contact with it.
iv
General Safety Considerations
General Safety Considerations
This product has been designed and tested in accordance with IEC Publication 1010, Safety Requirements for Electronic Measuring Apparatus, and has
been supplied in a safe condition. The instruction documentation contains
information and warnings which must be followed by the user to ensure safe
operation and to maintain the product in a safe condition.
WARNING
WARNING
If this product is not used as specified, the protection provided by the
equipment could be impaired. This product must be used in a normal
condition (in which all means for protection are intact) only.
No operator serviceable parts inside. Refer servicing to qualified
personnel. To prevent electrical shock, do not remove covers.
v
General Safety Considerations
vi
Contents
The HP 8702D—At a Glance iii
1 Getting Started
A Quick Tour 1-4
Changing Instrument Settings 1-12
Making Measurements Using Guided Setup 1-15
Setting the RF Output 1-21
Protecting Against Electrostatic Damage 1-31
Cleaning Connections for Accurate Measurements 1-33
2 Measuring Lightwave Sources
Making Transmission Measurements 2-4
Making Reflection Measurements 2-8
3 Measuring Lightwave Receivers
Making Transmission Measurements 3-4
Making Reflection Measurements 3-8
Measuring Phase Distortion 3-11
4 Measuring Electrical Devices
Measuring Magnitude and Insertion Phase Response 4-4
Measuring Electrical Length and Phase Distortion 4-9
Performing Time Domain Measurements 4-22
Reducing Receiver Crosstalk 4-30
Amplifier Testing 4-31
Performing Swept Power Measurements 4-35
Measuring Gain Compression 4-36
Measuring Gain and Reverse Isolation Simultaneously 4-40
Performing Harmonic Measurements
(Option 002) 4-42
Mixer Testing 4-46
Performing On-Wafer Measurements 4-62
Connection Considerations 4-63
5 Measuring Optical Devices
Making Transmission Measurements 5-4
Making Reflection Measurements 5-8
Contents-1
Contents
Making Time Domain Measurements 5-14
6 Optimizing Measurements
Display Functions 6-4
Increasing Measurement Accuracy 6-9
Changing the Display Format 6-12
Displaying and Saving Traces 6-21
Increasing Sweep Speed 6-25
Increasing Dynamic Range 6-30
Reducing Trace Noise 6-32
Reducing Receiver Crosstalk 6-37
Knowing the Instrument Modes 6-38
7 Measuring with Markers
General Information 7-4
Activating Markers 7-9
Setting the Measurement Range 7-12
Making Relative Measurements 7-20
Searching with Markers 7-24
Making Statistical Measurements 7-28
Using Markers with Other Display Formats 7-30
Making Other Measurements 7-34
8 Making Mixer Measurements
Measurement Considerations 8-3
Conversion Loss Using the Frequency Offset Mode 8-4
High Dynamic Range Swept RF/IF Conversion Loss 8-11
Conversion Loss Using the Tuned Receiver Mode 8-14
Phase or Group Delay Measurements 8-20
Conversion Compression Using the Frequency Offset Mode 8-23
Isolation Example Measurements 8-28
Power Meter Calibration for Mixer Measurements 8-34
9 Saving Data, States, and the Display
Saving Instrument States 9-4
Saving Measurement Data 9-7
Saving the Display to a File 9-10
Contents-2
Contents
Formatting Disks 9-11
If You Have Problems with Disk Storage 9-12
10 Using Limit Lines
General Information 10-4
Example 1. Creating Flat Limits 10-10
Example 2. Creating Sloping Limits 10-13
Example 3. Creating Single-Point Limits 10-15
11 Creating Sequences
General Information 11-4
Creating and Editing Sequences 11-12
Running Sequences 11-21
Saving and Printing 11-22
12 Printing and Plotting
Saving the Display to a File 12-4
Printing or Plotting the Display 12-5
Displaying Lists 12-7
Selecting Options 12-8
Connecting Printers, Plotters, and Disk Drives 12-17
If You Encounter Problems with Printing or Plotting 12-23
13 Performing Calibrations
Entering Calibration Kits and Standards 13-4
Modifying User-Defined Electrical Kits 13-7
Performing Error-Correction 13-13
Procedures for Error-Correcting Measurements 13-21
Modifying Optical Standards 13-53
Calibrating with a Power Meter 13-55
Contents-3
Contents
Contents-4
1
Getting Started
Getting Started
Getting Started
Getting Started
This chapter will introduce you to the HP 8702D’s basic features and controls.
It also shows how to make transmission and reflection measurements using
guided setups
measurement. Guided setups provide a fast and easy method of performing
lightwave measurements. After you become proficient at making simple measurements, read Chapter 2, “Measuring Lightwave Sources” through
Chapter 5, “Measuring Optical Devices”.
Read “Setting the RF Output” on page 1-21, to learn how to set the RF start
frequency, stop frequency, and power level for your measurements. Although
you can configure these settings from within guided setups, understanding
how to control them manually will help you to get the most from your measurements.
Be sure to read the last two sections of this chapter. They show you how to
protect your instrument from damage.
. Guided setups are a series of menus which step you through a
CAUTION
The HP 8702D’s
the center conductor of these connectors. Do not allow any static charge to
come into contact with them. To protect your instrument, study the
information located in “Protecting Against Electrostatic Damage” on page 1-31.
1-2
PORT 1
and
PORT 2
connectors are static sensitive. Do not touch
What you’ll find in this chapter
A Quick Tour 1-4
Front panel 1-4
Display 1-7
Rear panel 1-9
Changing Instrument Settings 1-12
Making Measurements Using Guided Setup 1-15
To make an O/E measurement 1-17
Setting the RF Output 1-21
Defining the frequency range 1-21
Understanding the power ranges 1-22
Power coupling options 1-23
Source attenuator switch protection 1-24
Sweep time 1-24
Sweep types 1-27
Alternate and chop sweep modes 1-29
Protecting Against Electrostatic Damage 1-31
Cleaning Connections for Accurate Measurements 1-33
Cleaning Optical Connectors 1-34
Cleaning Electrical Connections 1-40
Getting Started
Getting Started
1-3
Getting Started
A Quick Tour
A Quick Tour
Use this section to identify the instrument’s front and rear panel features and
to learn how to change the instrument’s settings.
Front panel
Figure 1-1. HP 8702D Front Panel
1
LINE switch. This switch controls ac power to the analyzer. 1 is on, 0 is off.
2
Display. This shows the measurement data traces, measurement annotation,
and softkey labels. The display is divided into specific information areas,
1-4
Getting Started
A Quick Tour
illustrated in Figure 1-2.
3
Softkeys. These keys provide access to menus that are shown on the display.
4
STIMULUS function block. The keys in this block allow you to control the
analyzer source’s frequency, power, and other stimulus functions.
5
RESPONSE function block. The keys in this block allow you to control the
measurement and display functions of the active display channel.
6
ACTIVE CHANNEL keys. The analyzer has two independent display channels.
These keys allow you to select the active channel. Then any function you enter
applies to this active channel.
7
The ENTRY block. This block includes the knob, the step (⇑, ⇓) keys, and the
number pad. These allow you to enter numerical data and control the markers.
8
INSTRUMENT STATE function block. These keys allow you to control
channel-independent system functions, such as the following:
• copying, save/recall, and HP-IB controller mode
• limit testing
• external source mode
• tuned receiver mode
• frequency offset mode
• test sequence function
• harmonic measurements (Option 002)
• time domain transform
HP-IB STATUS indicators are also included in this block.
PRESET
9
key. This key returns the instrument to either a known factory preset
state, or a user preset state that can be defined.
10
PORT 1 and PORT 2. These ports output a signal from the source and receive
input signals from a device under test. PORT 1 allows you to measure S
S
. PORT 2 allows you to measure S21 and S22.
11
Option 011 R, A, and B connector. These connectors allow you to apply input
signals when creating your own test setup. In addition these connectors allow
you to use the HP 85046A/B, HP 85047A, or HP 85044A/B test sets to simplify
measurement setup.
Option 011 RF OUT connector. This connects the RF output signal from the
analyzer’s internal source to a test set or power splitter.
11
PROBE POWER connector. This connector (fused inside the instrument)
supplies power to an active probe for in-circuit measurements of ac circuits.
12
and
1-5
Getting Started
A Quick Tour
12
R CHANNEL connectors. These connectors allow you to apply an input signal
to the analyzer’s R channel, for frequency offset mode.
13
Disk drive. This 3.5-inch drive allows you to store and recall instrument states
and measurement results for later analysis.
1-6
Display
Getting Started
A Quick Tour
Figure 1-2. Analyzer Display (Single Channel, Cartesian Format)
The analyzer display shows various measurement information:
• the grid where the analyzer plots the measurement data.
• the currently selected measurement parameters.
• the measurement data traces.
1
Stimulus Start Value. This value could be any one of the following:
• the start frequency of the source in frequency domain measurements.
• the start time in CW mode (0 seconds) or time domain measurements.
• the lower power value in power sweep.
When the stimulus is in center/span mode, the center stimulus value is shown
in this space.
2
Stimulus Stop Value. This value could be any one of the following:
• the stop frequency of the source in frequency domain measurements.
• the stop time in time domain measurements or CW sweeps.
• the upper limit of a power sweep.
1-7
Getting Started
A Quick Tour
When the stimulus is in center/span mode, the span is shown in this space. The
stimulus values can be blanked.
3
Status Notations. This area shows the current status of various functions for
the active channel.
4
Active Entry Area. This displays the active function and its current value.
5
Message Area. This displays prompts or error messages.
6
Title. This is a descriptive alpha-numeric string title that you define and enter
through an attached keyboard.
7
Active Channel. This is the number of the current active channel, selected with
ACTIVE CHANNEL
the
keys. If dual channel is on with an overlaid display, both
channel 1 and channel 2 appear in this area.
8
Measured Input(s). This shows the S-parameter, input, or ratio of inputs
currently measured, as selected using the
MEAS
key. Also indicated in this area
is the current display memory status.
9
Format. This is the display format that you selected using the
10
Scale/Div. This is the scale that you selected using the
SCALE REF
FORMAT
key, in units
appropriate to the current measurement.
11
Reference Level. This value is the reference line in Cartesian formats or the
outer circle in polar formats, whichever you selected using the
SCALE REF
The reference level is also indicated by a small triangle adjacent to the
graticule, at the left for channel 1 and at the right for channel 2.
12
Marker Values. These are the values of the active marker, in units appropriate
to the current measurement.
13
Marker Stats, Bandwidth. These are statistical marker values that the analyzer
calculates when you access the menus with the
14
Softkey Labels. These menu labels redefine the function of the softkeys that are
MARKER FCTN
key.
located to the right of the analyzer display.
15
Pass/Fail. During limit testing, the result will be annunciated as “PASS” if the
limits are not exceeded, and “FAIL” if any points exceed the limits.
key.
key.
1-8
Rear panel
Getting Started
A Quick Tour
Figure 1-3. HP 8702D Rear Panel
1
Serial number plate.
2
External Monitor. Red, green, and blue video output connectors provide analog
red, green, and blue video signals which you can use to drive an external
monitor, such as the HP 3571A/B, or monochrome monitor, such as the
HP 35731A/B. You can use other analog multi-sync monitors if they are
compatible with the analyzer’s 25.5 kHz scan rate and video levels: 1 V p-p,
0.7 V=white, 0 V=black, –0.3 V sync, sync on green.
3
HP-IB connector. This allows you to connect the analyzer to an external
controller, compatible peripherals, and other instruments for an automated
system.
4
PARALLEL connector. This connector allows the analyzer to output to a
peripheral with a parallel input. Also included, is a general purpose input/
output (GPIO) bus that can control eight output bits and read five input bits
through test sequencing.
5
RS-232 connector. This connector allows the analyzer to output to a peripheral
with an RS-232 (serial) input.
1-9
Getting Started
A Quick Tour
6
KEYBOARD input (DIN) connector. This connector allows you to connect an
external keyboard. This provides a more convenient means to enter a title for
storage files, as well as substitute for the analyzer’s front panel keyboard. The
keyboard must be connected to the analyzer before the power is switched on.
7
Power cord receptacle, with fuse.
8
Line voltage selector switch.
9
10 MHZ REFERENCE ADJUST. (Option 1D5)
10
10 MHZ PRECISION REFERENCE OUTPUT. (Option 1D5)
11
EXTERNAL REFERENCE INPUT connector. This allows for a frequency
reference signal input that can phase lock the analyzer to an external frequency
standard for increased frequency accuracy.
12
AUXILIARY INPUT connector. This allows for a dc or ac voltage input from an
external signal source, such as a detector or function generator, which you can
then measure, using the S-parameter menu.
13
EXTERNAL AM connector. This allows for an external analog signal input that
is applied to the ALC circuitry of the analyzer’s source. This input analog signal
amplitude modulates the RF output signal.
14
EXTERNAL TRIGGER connector. This allows connection of an external
negative-going TTL-compatible signal that will trigger a measurement sweep.
The trigger can be set to external through softkey functions.
15
TEST SEQUENCE. Outputs a TTL signal that can be programmed in a test
sequence to be high or low, or pulse (10 µseconds) high or low at the end of a
sweep for robotic part handler interface.
16
LIMIT TEST. Outputs a TTL signal of the limit test results as follows:
•Pass: TTL high
• Fail: TTL low
17
BIAS INPUTS AND FUSES. These connector bias devices connected to port 1
and port 2. The fuses (1 A, 125 V) protect the port 1 and port 2 bias lines.
18
TEST SET INTERCONNECT. This allows you to connect an HP 8702D
Option 011 analyzer to an HP 85046A/B or 85047A S-parameter test set using
the interconnect cable supplied with the test set. The S-parameter test set is
then fully controlled by the analyzer.
1-10
Figure 1-4. Rear Panel Connectors
Getting Started
A Quick Tour
1-11
Getting Started
Changing Instrument Settings
Changing Instrument Settings
Once a function is selected, by a front-panel key or softkey, it is “active” and
its value is shown in the display’s active function area. Use the numeric keypad, the knob, and the step keys to change the value of active functions. Generally, the keypad, knob, and step keys can be used interchangeably. If no
other functions are activated, the knob moves the active marker.
You can use the
well as any displayed prompts, error messages, or warnings. Use this function
to clear the display before plotting. This key is also helpful in preventing the
changing of active values by accidentally moving the knob.
Use the ← key to delete the last entry, or the last digit entered from the
numeric keypad.
ENTRY OFF
key to clear and turn off the active entry area, as
Terminating number entries
The units terminator keys are the four keys in the right column of the keypad.
You must use these keys to specify units of numerical entries from the keypad.
A numerical entry is incomplete until a terminator is supplied. The analyzer
indicates that an input is incomplete by a data entry arrow ← pointing at the
last entered digit in the active entry area. When you press the units terminator
key, the arrow is replaced by the units you selected.
Table 1-1. Unit Keys
Key Description
G/n
µ
M/
k/m
x1 basic units: dB, dBm, degrees, seconds, Hz, or dB/GHz (may be used to
1-12
Giga/nano (10
Mega/micro (106 / 10–6)
kilo/milli (10
terminate unitless entries, such as averaging factor)
9
/ 10–9)
3
/ 10–3)
Getting Started
Changing Instrument Settings
Stepping entry values up or down
You can use the step keys ↑ (up) and ↓ (down) to step the current value of the
active function up or down. The analyzer defines the steps for different functions. No units terminator is required.
PRESET
The
key sets the instrument to its default state
As you perform your measurements, remember that you can always return the
HP 8702D to its factory default settings by pressing the front-panel
Pressing
PRESET
also returns any guided setup settings to their default values.
PRESET
key.
If you leave guided setup by pressing some other key, you can return to your
last guided setup menu by pressing the front-panel
SYSTEM
key.
Two measurements can be displayed simultaneously
The analyzer has two digital channels for independent measurements. You can
view both the active and inactive channel traces, either overlaid or on separate
graticules one above the other (split display). The dual channel and split display features are accessed through the display menus.
The two channels allow you to measure and view two different sets of data
simultaneously. For example, the analyzer can display the reflection and
transmission characteristics of a device, or one measurement with two different frequency spans.
Use the
CHAN 1
and
CHAN 2
keys to select the “active channel.” All of the channel-specific keys that you select apply to the active channel. The current
active channel is indicated by an amber LED adjacent to the corresponding
channel key.
The two channels are normally coupled
Normally, the two channels are coupled. With the
COUPLED CH ON off
key set to
on (the preset condition), both channels have the same stimulus values (the
inactive channel takes on the stimulus values of the active channel).
In the stimulus coupled mode, the following parameters are coupled:
•frequency
• number of points
• source power
• number of groups
• power slope
• IF bandwidth
• sweep time
• trigger type
• gating parameters
1-13
Getting Started
Changing Instrument Settings
• sweep type
• harmonic measurement
• power meter calibration
You can uncouple the stimulus values between the two display channels by
pressing
COUPLED CH ON off
. This allows you to assign different stimulus values
for each channel; it’s almost like having the use of a second analyzer. The coupling and uncoupling of the stimulus values for the two channels is independent of the display and marker functions.
Coupling of stimulus values for the two channels is independent of
on OFF
in the display menu and
MARKERS: UNCOUPLED
in the marker mode menu.
DUAL CHAN
Measurement markers can have the same stimulus values (coupled) for the
two channels, or they can be uncoupled for independent control in each chan-
COUPLED CH on OFF
nel.
becomes an alternate sweep function when dual channel
display is on; in this mode the analyzer alternates between the two sets of
stimulus values for measurement of data and both are displayed.
1-14
Getting Started
Making Measurements Using Guided Setup
Making Measurements Using Guided Setup
In this section, you’ll learn how to make fast, easy measurements using the
HP 8702D’s guided setup feature. When you first turn on the instrument or
press the green
GUIDED SETUP
Guided setups contain the instructions you need to perform accurate measurements including:
• Diagrams of equipment connections.
• RF source’s start frequency, stop frequency, and power level.
•Calibration.
PRESET
key, the
, and follow the displayed instructions.
GUIDED SETUP
softkey is displayed. Simply press
The first step in the procedure is to select either
REFLECTION
the following four types of devices to measure:
• E/E (electrical device)
• E/O (lightwave source)
• O/E (lightwave receiver)
• O/O (optical device)
With reflection measurements, you select the type of port that you are characterizing on your device:
• 1-PORT ELECTRICAL
•1-PORT OPTICAL
In guided setups, always press
This section provides step-by-step instructions for characterizing an O/E
device. Because all of the guided setup procedures are similar, after performing this procedure, you should be able to perform any of the other procedures.
You’ll need HP 83400-series lightwave sources and receivers
For any measurements other than E/E or 1-PORT ELECTRICAL, you’ll need
HP 83400-series lightwave sources and receivers to provide modulation and
and demodulation of the light signal. These sources and receivers come with
measurements. With bandwidth measurements, you select one of
CONTINUE
to display the next set of instructions.
BANDWIDTH
(transmission) or
1-15
Getting Started
Making Measurements Using Guided Setup
calibration data that is stored on a 3.5 inch diskette. During a guided setup
procedure, you’ll be prompted to insert the disk into the HP 8702D’s frontpanel disk drive in order to read the calibration data.
Calibration improves measurement accuracy
An important part of making measurements, including those in guided setups,
is performing a calibration. Calibration removes certain repeatable errors from
your measurements that are associated with the test setup. During guided
setup procedures, you’ll perform a
RESPONSE
calibration. This calibration corrects for the test setup’s frequency response. During E/O and O/E procedures
you can choose to perform a
bration is more accurate but requires several additional steps. A
MATCH
calibration characterizes the test setup at the measurement plane. This
RESPONSE & MATCH
calibration instead. This cali-
RESPONSE &
involves temporarily disconnecting the source or receiver and measuring
open, short, and load calibration standards.
You’ll need an HP calibration kit
HP calibration kits include the open, short, and load required to make
RESPONSE & MATCH
calibrations during measurements.
HP 83400 substitution during calibration
Whenever you’re characterizing an E/O or O/E device, the calibration is performed after temporarily substituting an HP 83400 source or receiver for the
device you’re testing. After the calibration has completed, your device is reinserted into the test setup, and the measurement is performed. For example,
suppose that you want to measure the bandpass of an E/O device. You first
connect the test setup using your device and an HP 83400-series lightwave
receiver. During the first part of the guided setup procedure, you’ll set the
measurement parameters. Then during calibration, you’ll remove your device
and substitute an HP 83400-series lightwave source. After the calibration is
complete, the procedure prompts you to remove the HP 83400-series lightwave source and re-insert your test device.
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Getting Started
Making Measurements Using Guided Setup
To make an O/E measurement
This step-by-step procedure takes you through the measurement of a typical
O/E device. During the procedure, you’ll perform a
tion. If your device requires different measurement parameters (for example,
the start frequency), simply change them as needed.
In order to perform this procedure, you’ll need an HP 83400-series lightwave
receiver with its calibration data disk, a lightwave source, an HP calibration
kit, and a receiver that you want to characterize.
1
Connect the test equipment as shown in the following figure.
RESPONSE & MATCH
calibra-
Figure 1-5. Initial test setup
2
3
4
5
PRESET
Press
Press
Press
Use the
modulation. Then, press
to set the instrument to its default condition.
GUIDED SETUP, BANDWIDTH
O/E, CONTINUE,
START
and
STOP
, and then
and then
CONTINUE
softkeys to enter the frequency limits for the
CONTINUE
.
CONTINUE
.
.
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Getting Started
Making Measurements Using Guided Setup
NUMBER OF POINTS
The
softkey allows you to change the number of measurement points taken during each sweep. The default setting is normally adequate for most measurements.
6
Use the
CONTINUE
Use the
RF SOURCE POWER
.
SWEEP TIME
softkey to decrease the sweep time if needed. Although
softkey to set the power level, and then press
this results in faster measurements, sweeps that are too fast will distort the
displayed response. If this happens, increase the sweep time until changes no
longer effect the displayed trace.
7
RESPONSE & MATCH
Press
to select the most extensive calibration procedure.
Because you’re performing the additional electrical match calibration, you’ll
need a calibration kit which includes open, short, and load calibration standards.
8
9
CAL KIT
Press
PRIOR MENU
DEFINE RECEIVER
Press
, and select the calibration kit that you will be using. Then press
.
. Insert the calibration disk that came with the HP 83400-
series lightwave receiver into the HP 8702D’s front-panel disk drive.
10
11
LOAD DISK CAL DATA
Press
RCVR1 DISK
. Then press
, and when the data is finished loading, press
CONTINUE
.
Disconnect the RF cable from the input to the lightwave source. If an adapter
is needed to make the RF thru connection described in Step 13, it should be
connected between the RF cable and the open, short, and load.Connect the
“open” connector from the calibration kit. Step through the menus measuring
the open, short, and broadband (load). For the remainder of the test, do not
disconnect the cable from the HP 8702D. Refer to Figure 1-6 on page 1-19.
LOAD
12
Disconnect the RF cable from the output of the lightwave receiver. Connect the
“open” connector from the calibration kit. Step through the menus measuring
the open, short, and broadband (load). For the remainder of the test, do not
disconnect the cable from the HP 8702D.
13
Use an RF “through” connector to connect the two RF cables together. Press
RF THRU
14
Connect the lightwave source and lightwave receiver as shown on the
and then
DONE: RF THRU
.
HP 8702D’s display. Refer to Figure 1-7 on page 1-19.
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Figure 1-6. Match calibration
Getting Started
Making Measurements Using Guided Setup
Figure 1-7. Calibration with lightwave receiver
15
16
Press
Press
RECEIVER
DISK (1)
and then
and then
DONE RECEIVER
DONE: SRC + RCVR
.
.
1-19
Getting Started
Making Measurements Using Guided Setup
17
Is the noise floor higher than the crosstalk?
• Yes—press
OMIT ISOLATION
, and then press
DONE: ISOL’N STD
.
• No—disconnect the fiber-optic cable from the lightwave source’s output
connector, and press
DONE: ISOL’N STD
press
ISOLN LOAD
.
. Reconnect the fiber-optic cable, and then
• If you are not sure, then omit isolation.
18
Remove the HP 83400-series lightwave receiver, and replace it with the
receiver that you want to test.
Figure 1-8. Final setup for measurements
19
Press
VIEW MEASURE
. The bandpass measurement of your receiver is shown on
the display.
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