Wiltron 681 B Series User manual

490 JARVIS DRIVE
MORGAN HILL, CA 95037-2809
SERIES
681XXB
SYNTHESIZED SWEEP GENERATOR
OPERATION MANUAL
P/N: 10370-10258
REVISION: B
PRINTED: FEBRUARY 1995
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
WILTRON manufactured 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, or operation outside of 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.
NOTICE
WILTRON Company has prepared this manual for use by WILTRON Company personnel and
customers as a guide for the proper installation,operation, andmaintenance of WILTRON Company
equipment and computor programs. The drawings, specifications, and information contained herein
are the property of WILTRON Company, and any unauthorized use or disclosure of these drawings,
specifications, and information is prohibited; they shall not be reproduced, copied, or used in whole
or in part as the basis for manufacture or sale of the equipment or software programs without the
prior writtten consent of WILTRON Company.

Declaration of Conformity
Application of Council Directive: EMC- 89/336/EEC
Manufacturer: Wiltron Company
490 Jarvis Drive
Morgan Hill, CA 95037
USA
Products: Synthesized CW / Sweep / Signal Generators
Models: 680XXB, 681XXB, 682XXB, 683XXB
Standards: EN 55011: 1991, Group 1, Class A
EN 50082-1: 1992
IEC 801-2, 1991, Level 3
IEC 801-3, 1984, Level 2
IEC 801-4, 1988, Level 2
Signature Date
John Pink
Managing Director
Wiltron Measurements LTD.
Wiltron House
Rutherford Close
Stevenage
Herts, SG1 2EF
UNITED KINGDOM

TABLE OF CONTENTS
Chapter 1 — General Information
Chapter 1 provides general information about the WILTRON Series 681XXB 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 681XXB 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 681XXB 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 681XXB 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 681XXB 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.
Operator maintenance is limited to basic troubleshooting and repairs that can be made without re-
moving the instrument covers. Chapter contents are detailed immediately following the tab.
Chapter 7 — Use With Other Instruments
Chapter 7 provides information and instructions for using the Series 681XXB Synthesized Sweep
Generator with other WILTRON instruments. Chapter contents are detailed immediately following
the tab.
681XXB OM i

Appendix A — Rear Panel Connectors
Appendix A provides descriptions of the rear panel connectors on a typical Series 681XXB 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 681XXB 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 681XXB 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 . . . . . . . . . . . . 1-5
1-5 RELATED MANUALS . . . . . . . . . . . . . . . . 1-5
GPIB Programming Manual 1-5
SCPI Programming Manual 1-5
Maintenance Manual 1-5
1-6 OPTIONS . . . . . . . . . . . . . . . . . . . . . . . 1-6
1-7 PERFORMANCE SPECIFICATIONS . . . . . . . 1-6
1-8 RECOMMENDED TEST EQUIPMENT . . . . . . 1-7
Chapter 1
General Information

Figure 1-1. Series 681XXB 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 681XXB Synthesized Sweep Gen-
erator. (Throughout this manual, the terms 681XXB 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 681XXB
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 681XXB Synthesized 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 six models covering a variety of fre-
quency and power ranges. Table 1-1, on page 1-4, lists models, fre-
quency ranges, and maximum leveled output.
681XXB OM 1-3

GENERAL 681XXB
INFORMATION MODELS
681XXB
Model Frequency (GHz) Output Power Output Power w/Optional Attenuator
68137B 2.0 – 20.0 GHz +13 dBm +11 dBm
68147B 0.01 – 20.0 GHz +13 dBm +11 dBm
68153B 2.0 – 20.0 GHz
20.0 – 26.5 GHz +9 dBm +6 dBm +7 dBm +3.5 dBm
68159B 0.01 – 2.0 GHz 2.0 – 20.0 GHz
20.0 – 26.5 GHz
+13 dBm
+9 dBm
+6 dBm
+11 dBm
+7 dBm
+3.5 dBm
68163B 2.0 – 20.0 GHz
20.0 – 40.0 GHz +9 dBm +6 dBm +7 dBm +3 dBm
68169B 0.01 – 2.0 GHz 2.0 – 20.0 GHz
20.0 – 40.0 GHz
+13 dBm
+9 dBm
+6 dBm
+11 dBm
+7 dBm
+3 dBm
With Option 15 (High Power) Installed
68137B 2.0 – 20.0 GHz +17 dBm +15 dBm
68147B 0.01 – 2.0 GHz
2.0 – 20.0 GHz +13 dBm +17 dBm +11 dBm +15 dBm
68153B 2.0 – 20.0 GHz
20.0 – 26.5 GHz +13 dBm +10 dBm +11 dBm +7.5 dBm
68159B 0.01 – 2.0 GHz 2.0 – 20.0 GHz
20.0 – 26.5 GHz
+13 dBm
+13 dBm
+10 dBm
+11 dBm
+11 dBm
+7.5 dBm
68163B 2.0 – 20.0 GHz
20.0 – 40.0 GHz +13 dBm +6 dBm +11 dBm +3 dBm
68169B 0.01 – 2.0 GHz 2.0 – 20.0 GHz
20.0 – 40.0 GHz
+13 dBm
+13 dBm
+6 dBm
+11 dBm
+11 dBm
+3 dBm
Table 1-1. Series 681XXB Models
1-4 681XXB OM

1-4 IDENTIFICATION NUMBER All WILTRON instruments are assigned a unique six-digit ID number,
such as “301001”. 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 68147B Synthesized Sweep
Generator, Serial No. 301001).
1-5 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
This manual provides information for remote opera-
tion of the sweep generator with 681XXB 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 com-
plete listing and description of all 681XXB GPIB
Product Specific commands, and several program-
ming examples. The WILTRON part number for the
GPIB Programming Manual is 10370-10260.
SCPI
Programming
Manual
This manual provides information for remote opera-
tion of the sweep 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 681XXB
SCPI command set, and examples of command us-
age. The WILTRON part number for the SCPI Pro-
gramming Manual is 10370-10274.
Maintenance
Manual The Maintenance Manual supplies service informa- tion for all models in the 681XXB series. The service
information includes functional circuit descriptions,
block diagrams, performance verification tests, cali-
bration procedures, troubleshooting data, and assem-
bly and component removal/replacement procedures.
The WILTRON part number for the Maintenance
Manual is 10370-10262.
GENERAL IDENTIFICATION
INFORMATION NUMBER
681XXB OM 1-5

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 ≤26.5 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 fre-
quency of ≤40 GHz. Output power is selected directly in dBm on
the front panel (or via GPIB). Rated RF output power is reduced.
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 con-
sole.
Option 15, High Power Output. Adds high-power RF compo-
nents to the instrument providing 50 mW RF output power in the
2–26.5 GHz frequency range.
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.
Option 19, SCPI Programmability. Adds GPIB command mne-
monics complying with Standard Commands for Programmable
Instruments (SCPI), Version 1993.0. SCPI programming complies
with IEEE 488.2-1987.
1-7 PERFORMANCE
SPECIFICATIONS
Series 681XXB Synthesized Sweep Generator performance specifica-
tions are provided in Appendix B.
K Connector ®is a registered trademark of WILTRON Company.
GENERAL
INFORMATION OPTIONS
1-6 681XXB OM

1-8 RECOMMENDED TEST
EQUIPMENT
Table 1-2 lists the recommended test equipment for performing the Se-
ries 681XXB Synthesized 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
681XXB 0M 1-7/1-8

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 PREPARATION FOR STORAGE/SHIPMENT . . . 2-10
Preparation for Storage . . . . . . . . . . . . . . . 2-10
Preparation for Shipment . . . . . . . . . . . . . 2-10
Chapter 2
Installation

Chapter 2
Installation
2-1 INTRODUCTION This chapter provides installation instructions for the Series 681XXB
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.
681XXB OM 2-3

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
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 90 to 132 Vac and 180 to 264 Vac, 48 to 400 Hz, single-phase power. Power
consumption is 400 VAmaximum.
Line Voltage
Selection 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
681XXB accepts 90 to 132 Vac line voltage. When
the switch is set to 220 Vac, the 681XXB accepts 180
to 264 Vac line voltage. If the selector setting is incor-
rect 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.
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
681XXB.
Power
Connection Connecting the 681XXB 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 three-
wire power line outlet.
PREPARATION
INSTALLATION FOR USE
2-4 681XXB OM

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
681XXB from OPERATE (green LED on) to
STANDBY (orange LED on).
NOTE
During standby operation, the fan runs
continuously.
PREPARATION
INSTALLATION FOR USE
LINE
OPERATE
STANDBY
SYSTEM
MODULATION
LEVEL
CONTROL
Line
Key
Line Voltage
Selector Switch
Line
Fuse
GPIB
Connector
Figure 2-1. Sweep Generator Rear Panel showing Power Connection
681XXB 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 681XXB
requires approximately 72 hours (3 days) of warm
up to achieve 5 x 10–10/day frequency accuracy and
stability.
When placing the 681XXB in operation from stand-
by, allow 30 minutes warmup to assure stable opera-
tion.
Operating
Environment The 681XXB 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 681XXB in 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 681XXB OM

2-4 GPIB SETUPAND
INTERCONNECTION
The 681XXB 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 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 2-1 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.
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 on the following page) is dis-
played.
GPIB SETUP AND
INSTALLATION INTERCONNECTION
681XXB OM 2-7

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 below) is displayed.
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.
GPIB SETUP AND
INSTALLATION INTERCONNECTION
2-8 681XXB OM

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.
Selecting the
Interface
Language
Series 681XXB Synthesized Sweep 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
681XXB GPIB Product Specific commands to control
the instrument; the SCPI interface language uses a
set of the Standard Commands for Programmable In-
struments commands to control the unit.
The Configure GPIB Menu has an additional menu
display. For instruments with Option 19, selection of
which external interface language is to be used is
made from this additional menu. From the Config-
ure GPIB Menu display, you can access the addi-
tional menu by pressing More . The additional Con-
figure GPIB Menu (shown 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.
GPIB SETUP AND
INSTALLATION INTERCONNECTION
681XXB OM 2-9