Wiltron 681 A Series User manual

490 JARVIS DRIVE
MORGAN HILL, CA 95037-2809
SERIES
681XXA
SYNTHESIZED SWEEP GENERATOR
OPERATION MANUAL
P/N: 10370-10250
REVISION: A
PRINTED: JANUARY 1993
COPYRIGHT 1993 WILTRON CO.

WARRANTY
The WILTRON product(s) listed on the title page is (are) warranted against defects in materials
and workmanship for one year from the date of shipment, except for YIG-tuned oscillators and all
microwave components, which are warranted for two years.
WILTRON’s obligation covers repairing or replacing products which prove to be defective during
the warranty period. Buyers shall prepay transportation charges for equipment returned to WIL-
TRON for warranty repairs. Obligation is limited to the original purchaser. WILTRON is not liable
for consequential damages.
LIMITATION OF WARRANTY
The foregoing warranty does not apply to WILTRON connectors that have failed due to normal
wear. Also, the warranty does not apply to defects resulting from improper or inadequate mainte-
nance by the Buyer, unauthorized modification or misuse, oroperation outsideof the environmental
specifications of the product. No other warranty is expressed or implied, and the remedies provided
herein are the Buyer’s sole and exclusive remedies.

TABLE OF CONTENTS
Chapter 1 — General Information
Chapter 1 provides general information about the WILTRON Series 681XXA Synthesized Sweep
Generator. It includes a general description of the sweep generator and information on its identifi-
cation number, related manuals, options, and performance specifications. A listing of recommended
test equipment is also provided. Chapter contents are detailed immediately following the tab.
Chapter 2 — Installation
Chapter 2 provides installation instructions for the Series 681XXA Synthesized Sweep Generator.
It includes information on initial inspection, preparation for use, storage, and reshipment, and
GPIB setup and interconnections. Chapter contents are detailed immediately following the tab.
Chapter 3 — Local (Front Panel) Operation
Chapter 3 provides information and instructions for operating the Series 681XXA Synthesized
Sweep Generator using the front panel controls. It includes illustrations of the front panel, data dis-
play area, and data entry area; an annotated diagram of the menu display format; and instructions
for performing sweep generator operations. Chapter contents are detailed immediately following
the tab.
Chapter 4 — Local Operation—Menu Maps
Chapter 4 provides menu maps that support the local (front panel) operating instructions found in
Chapter 3. It includes menu maps for all of the frequency, power level, and modulation modes of op-
eration plus system configuration. Chapter contents are detailed immediately following the tab.
Chapter 5 — Operation Verification
Chapter 5 provides three operation verification tests that can be used to verify Series 681XXA Syn-
thesized Sweep Generator operation. Setup instructions and step-by-step procedures are included
for each test. Test results can be compared with the specified limits shown on the test record forms
that are provided for each 681XXA model configuration. Chapter contents are detailed immediately
following the tab.
Chapter 6 — Operator Maintenance
Chapter 6 provides the information necessary for operator maintenance of the sweep generator. Op-
erator maintenance is limited to basic troubleshooting and repairs that can be made without remov-
ing the instrument covers. Chapter contents are detailed immediately following the tab.
681XXA OM i

Appendix A — Rear Panel Connectors
Appendix A provides descriptions of the rear panel connectors on a typical Series 681XXA Synthe-
sized Sweep Generator. It includes pinout diagrams and descriptions for the AUX I/O and IEEE-
488 GPIB connectors.
Appendix B — Performance Specifications
Appendix B lists the performance specifications for the Series 681XXA Synthesized Sweep
Generator.
Supplements
This tab provides a repository for application notes and other material used to supplement manual
chapters.
Index
Provides a subject index.
Table of Contents (Continued)
ii 681XXA OM

Table of Contents
1-1 SCOPE OF MANUAL . . . . . . . . . . . . . . . . 1-3
1-2 INTRODUCTION . . . . . . . . . . . . . . . . . . 1-3
1-3 DESCRIPTION . . . . . . . . . . . . . . . . . . . . 1-3
1-4 IDENTIFICATION NUMBER . . . . . . . . . . . . 1-4
1-5 RELATED MANUALS . . . . . . . . . . . . . . . . 1-4
1-6 OPTIONS . . . . . . . . . . . . . . . . . . . . . . . 1-4
1-7 PERFORMANCE SPECIFICATIONS . . . . . . . 1-5
1-8 RECOMMENDED TEST EQUIPMENT . . . . . . 1-6
Chapter 1
General Information

Figure 1-1. Series 681XXA Synthesized Sweep Generator

Chapter 1
General Information
1-1 SCOPE OF MANUAL This manual provides general information, installation, and operating
information for the WILTRON Series 681XXASynthesized Sweep Gen-
erator. (Throughout this manual, the terms 681XXA and sweep gener-
ator will be used interchangeably to refer to the instrument.) Manual
organization is shown in the table of contents.
1-2 INTRODUCTION This chapter contains general information about the series 681XXA
sweep generators. It includes a general description of the instrument
and information on its identification number, related manuals, options,
and performance specifications. Alisting of recommended test equip-
ment is also provided.
1-3 DESCRIPTION The Series 681XXASynthesized Sweep Generators are microprocessor-
based, synthesized signal sources with high resolution phase-lock capa-
bility. They generate both broad (full range) and narrow band sweeps
and discrete CW frequencies across the frequency range of 10 MHz to
40 GHz. All functions of the sweep generator are fully controllable lo-
cally 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 four models covering a variety of fre-
quency and power ranges. Table 1-1 lists all of the present models,
their frequency range, and their maximum leveled output power.
681XXA
Model Frequency (GHz) Output Power Output Power w/Optional Attenuator
68137A 2.0-20.0 GHz +13 dBm +10 dBm
68137A
w/Hi Pwr
Option 2.0-20.0 GHz +17 dBm +14 dBm
68147A 0.01-20.0 GHz +13 dBm +10 dBm
68147A
w/Hi Pwr
Option
0.01-2.0 GHz
2.0 -20.0 GHz +13 dBm +17 dBm +10 dBm +14 dBm
68163A 2.0-40.0 GHz +6 dBm +2 dBm
Table 1-1. Series 681XXA Models
681XXA OM 1-3

1-4 IDENTIFICATION NUMBER All WILTRON instruments are assigned a unique six-digit ID number,
such as “201001”. 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 WILTRON Customer Serv-
ice, please use the correct serial number with reference to the specific
instrument’s model number (i.e., Model 68147ASynthesized Sweep
Generator, Serial No. 201001).
1-5 RELATED MANUALS This is one of a three manual set that consists of an Operation Manual
(OM) , a Programming Manual (PM), and a Maintenance Manual
(MM). The PM provides programming information for remote opera-
tion of the series 681XXAsweep generator via the IEEE 488 interface
bus (GPIB) . It contains a general description of the GPIB, a brief intro-
duction to Standard Commands for Programmable Instruments (SCPI)
programming, and lists and describes all SCPI commands currently im-
plemented by the sweep generator. The WILTRON part number for the
PM is 10370-10254.
The MM supplies service information for all models in the 681XXAse-
ries. The service information includes functional circuit descriptions,
block diagrams, performance verification tests, calibration procedures,
troubleshooting data, maintenance procedures, and assembly-level
drawings. The WILTRON part number for the MM is 10370-10252.
1-6 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
handles for mounting the instrument in a standard 19-inch equip-
ment 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 fre-
quency of ≤20 GHz. Output power is selected directly in dBm on
the front panel (or via GPIB) over a 122 dB range. Rated output
power is reduced by 3 dB.
Option 2B, 110 dB Step Attenuator. Adds a 10 dB per step
attenuator with a 110 dB range for models having a high-end fre-
quency of ≤40 GHz. Output power is selected directly in dBm on
the front panel (or via GPIB) over a 122 dB range. Rated output
power is reduced by 4 dB.
GENERAL IDENTIFICATION
INFORMATION NUMBER
1-4 681XXA OM

Option 9K, Rear Panel RF Output. Adds an RF output connec-
tor (K-Connector ®, female) to the rear panel and deletes the RF
output connector on the front panel.
Option 11, 0.1 Hz Frequency Resolution. Provides frequency
resolution of 0.1 Hz.
Option 14, WILTRON 360B VNACompatibility. Modifies rack
mounting hardware to mate unit in a Wiltron 360B VNA console.
Option 15, High Power Output. Adds high-power RF compo-
nents to the instrument providing 50 mW RF output power in the
2–20 GHz frequency range. This option is only available for mod-
els 68137A and 68147A .
Option 16, High-Stability Time Base. Adds an ovenized,
10 MHz crystal oscillator with <5 x 10–10/day frequency stability.
Option 17, No Front Panel. Deletes the front panel for use in
remote control applications where a front panel display or key-
board control are not needed.
1-7 PERFORMANCE
SPECIFICATIONS
System performance specifications are provided in Appendix B.
GENERAL PERFORMANCE
INFORMATION SPECIFICATIONS
K Connector ®is a registered trademark of WILTRON Company.
681XXA OM 1-5

1-8 RECOMMENDED TEST
EQUIPMENT
Table 1-2 lists the recommended test equipment for performing the Se-
ries 681XXASynthesized Sweep Generator operation verification tests
in Chapter 5.
Instrument Critical Specification Recommended Manufacturer/Model
Frequency
Counter,
with
External Mixer
Range: 0.01 to 40 GHz
Input Z: 50 Ω
Resolution: 1 Hz
Other: External Time Base
Input
EIP Microwave, Inc. Model 578A, with
External Mixer:
Option 91 (26.5 to 40 GHz)
Power Meter,
with
Power
Sensor
Range: –30 to +20 dBm
(1µW to 100 mW) Hewlett-Packard Model 437B,
with
Power Sensor:
HP 8487A (0.01 to 50 GHz)
Oscilloscope
Bandwidth: DC to 150 MHz
Vertical Sensitivity: 2 mV/
division
Horiz Sensitivity: 50 ns/
division
Tektronix, Inc. Model 2445
Table 1-2. Recommended Test Equipment
GENERAL RECOMMENDED
INFORMATION TEST EQUIPMENT
1-6 681XXA OM

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 . . . . . . . . . . . . . . . . . . 2-5
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 . . . . . . . . . . . . . . . 2-8
Setting the GPIB Address . . . . . . . . . . . . . 2-8
Selecting the Line Terminator . . . . . . . . . . . 2-9
Selecting a GPIB Emulation . . . . . . . . . . . . 2-10
2-5 PREPARATION FOR STORAGE/SHIPMENT . . . 2-11
Preparation for Storage . . . . . . . . . . . . . . . 2-11
Preparation for Shipment . . . . . . . . . . . . . 2-11
Chapter 2
Installation

Chapter 2
Installation
2-1 INTRODUCTION This chapter provides installation instructions for the Series 681XXA
Synthesized Sweep Generator. It includes information on initial inspec-
tion, preparation for use, storage, and reshipment, and General Pur-
pose Interface Bus (GPIB) setup and interconnections.
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 ship-
ment have been checked against the packing list and the sweep gener-
ator has been checked for mechanical and electrical operation.
If the shipment is incomplete or if the sweep generator is damaged me-
chanically or electrically, notify your local sales representative or WIL-
TRON Customer Service. If either the shipping container is damaged
or the cushioning material shows signs of stress, notify the carrier as
well as WILTRON. Keep the shipping materials for the carrier’s inspec-
tion.
681XXA OM 2-3

2-3 PREPARATION FOR USE Preparation for use consists of checking that the rear panel line volt-
age module is set for the correct line voltage and connecting the sweep
generator to the power source. The following paragraphs provide these
procedures along with information about power requirements, warmup
times, and the operating environment.
Power
Requirements The sweep generator accepts 115Vac ±20% and
230Vac ±20%, 48 to 400 Hz, single-phase power.
Power consumption is 400 VA maximum.
Line Voltage
Selection The voltage selector drum of the rear panel line volt- age module can be set for either 115 Vac or 230 Vac
operation (Figure 2-1). If the selector drum setting is
incorrect for the line voltage available, change it to
the correct setting as follows:
Step 1. Remove the power cord from the line voltage module.
Step 2. Insert the blade of a small screwdriver into the slot
at the top-center of the module, and pry open the
cover.
Step 3. Remove the voltage selector drum by pulling it
straight out.
Step 4. Rotate the drum so that the desired line voltage
marking faces out, then reinstall the drum.
Step 5. Close the cover. Check that the desired line voltage
value is displayed through the opening in the cover.
Step 6. Reinstall the power cord.
PREPARATION
INSTALLATION FOR USE
Fuse Cavity
Voltage
Selector
Drum
Figure 2-1. Sweep Generator Rear Panel Line Voltage Module (Internal View)
2-4 681XXA OM

CAUTION
To avoid possible equipment damage, the instrument cabinet
should be grounded. Always use a three-wire power cable
connected to a three-wire power line outlet to power the
681XXA.
Power
Connection Connecting the 681XXAto 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 receptacle on
the line voltage module (Figure 2-2). Then plug the
male end of the power cord into a three-wire power
line outlet.
Standby Op-
eration Whenever the sweep 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
681XXAfrom OPERATE (green LED on) to
STANDBY (orange LED on).
NOTE
During standby operation, the fan runs
continuously.
Figure 2-2. Sweep Generator Rear Panel showing Power Connection
PREPARATION
INSTALLATION FOR USE
LINE
OPERATE
STANDBY
SYSTEM
MODULATION
LEVEL
CONTROL
Line
Key
681XXA OM 2-5

Warmup
Time From a cold start (ac power application), the sweep generator requires approximately 120 hours (5 days)
of warm up to achieve 1 x 10–7/day frequency accu-
racy and stability.
If the Option 16 time base is installed, the 681XXA
requires approximately 72 hours (3 days) of warm
up to achieve 5 x 10–10/day frequency accuracy and
stability.
When placing the 681XXAin operation from stand-
by, allow 30 minutes warmup to assure stable opera-
tion.
Operating
Environment The 681XXA can be operated within the following en- vironmental limits.
Temperature. 0°C to 55°C (-32°F to 131°F).
Humidity. 5 to 95% relative at 40°C.
Altitude. up to 4600 meters (approximately
15,000 feet).
Cooling. Internal cooling is provided by forced
airflow from the fan mounted on the rear panel.
CAUTION
Before installing the 681XXAin its operat-
ing environment, ensure that all airflow
passages at the sides and rear of the in-
strument are clear. This is of particular
importance whenever the instrument is
being rack-mounted.
PREPARATION
INSTALLATION FOR USE
2-6 681XXA OM

2-4 GPIB SETUPAND
INTERCONNECTION
The 681XXAprovides automated microwave signal generation via the
GPIB. The following paragraphs provide information about interface
connections, cable requirements, and the addressing of the sweep gen-
erator.
Interface
Connector Interface between the sweep 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 sin-
gle device. Figure 2-3 shows the location of the rear
panel GPIB connector.
Cable Length
Restrictions 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 instru-
ments or 20 meters—whichever is less.
GPIB SETUP AND
INSTALLATION INTERCONNECTION
IEEE-488 GPIB
GPIB Connector
CAUTION
DO NOT OPERATE
WITH POWER CORD
UNGROUNDED
FUSE
5A SB
2 REQUIRED
INPUT
115VAC
±
20%
230VAC
± 20%
48-400Hz
Figure 2-3. Sweep Generator Rear Panel GPIB Connector
681XXA OM 2-7

NOTE
For low EMI applications, the GPIB cable
should be a fully shielded type, with well-
grounded metal-shell connectors
GPIB Inter-
connection The only interconnection required for GPIB opera- tion is between the sweep generator and the control-
ler. This interconnection is via a standard GPIB
cable. The WILTRON Part number for such a cable
is 2000-1, -2, or -4 (1, 2, or 4 meters in length).
Setting the
GPIB
Address
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 below) is displayed.
Now press the menu soft-key Config . The System
Configuration Menu (shown below) is displayed.
To go to the Configure GPIB menu from this menu,
press the menu soft-key GPIB . The Configure
GPIB Menu (shown on the next page) is displayed.
GPIB SETUP AND
INSTALLATION INTERCONNECTION
2-8 681XXA OM

Press the menu soft-key GPIB Address to change
the current GPIB address of the sweep generator.
Enter a new address using the cursor control key or
the data entry keypad and the terminator key
Hz
ns
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.
Selecting
the Line
Terminator
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.
GPIB SETUP AND
INSTALLATION INTERCONNECTION
681XXA OM 2-9

Selecting a
GPIB
Emulation
The programming interface language for the series
681XXAsweep generator is Standard Commands for
Programmable Instruments (SCPI) version 1991.0.
In addition, the sweep generator is able to emulate
several signal sources. It responds to the published
GPIB commands of the following signal sources:
WILTRON Model 6600
WILTRON Model 6700
GPIB SETUP AND
INSTALLATION INTERCONNECTION
2-10 681XXA OM

2-5 PREPARATION FOR
STORAGE/SHIPMENT
The following paragraphs give instructions for preparing the 681XXA
for storage or shipment.
Preparation
for Storage Preparing the sweep 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 (–40°F to +176°F ).
Preparation
for Shipment To provide maximum protection against damage in transit, the sweep generator should be repackaged
in the original shipping container. If this container is
no longer available and the unit is being returned to
WILTRON for repair, advise WILTRON Customer
Service; 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 275-
pound test strength. This carton should have inside di-
mensions of no less than six inches larger than the unit
dimensions to allow for cushioning.
Protect the Instrument.
Surround the unit with polyethylene sheeting to pro-
tect the finish.
Cushion the Instrument.
Cushion the instrument on all sides by tightly packing
dunnage or urethane foam between the carton and the
unit. Provide at least three inches of dunnage on all
sides.
Seal the Container.
Seal the carton by using either shipping tape or an in-
dustrial stapler.
Address the Container.
If the instrument is being returned toWILTRON for
service, mark the address of the appropriate WILTRON
service center (Table 2-1) and your return address on
the carton in one or more prominent locations.
PREPARATION FOR
INSTALLATION STORAGE/SHIPMENT
681XXA OM 2-11