MS462XX Maintenance Manual.pdf part of Anritsu MS462xx MS462XX Maintenance Manual.pdf, Vector Network Measerument System Maintenance Manual text manual preview

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Caution
Do not exceed the operating input power level, voltage level, current level, and signal type that is appropriate for the instrument being used. Refer to your instrument's operation manual for safe operating practices and device limitations. Electrostatic Discharge (ESD) can damage the highly sensitive circuits in the instrument. ESD is most likely to occur as test devices are being connected to, or disconnected from, the instrument's front and rear panel ports and connectors. You can protect the instrument and test devices by wearing a static-discharge wristband. Alternatively, you can ground yourself to discharge any static charge by touching the outer chassis of the grounded instrument before touching the instrument's front and rear panel ports and connectors. Avoid touching the test port center conductors unless you are properly grounded and have eliminated the possibility of static discharge. Repair of damage that is found to be caused by electrostatic discharge is not covered under warranty.

MS462XX VECTOR NETWORK MEASUREMENT SYSTEM MAINTENANCE MANUAL

490 JARVIS DRIVE · MORGAN HILL, CA 95037-2809

P/N: 10410-00205 REVISION: J PRINTED: APRIL 2012 COPYRIGHT 2004 - 2012 ANRITSU CO.

WARRANTY
The Anritsu product(s) listed on the title page is (are) warranted against defects in materials and workmanship for three years 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 to Anritsu for warranty repairs. Obligation is limited to the original purchaser. Anritsu is not liable for consequential 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 resulting from improper or inadequate maintenance 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.

TRADEMARK ACKNOWLEDGMENTS
V Connector and K Connector are registered trademarks of Anritsu Company. HP 437B, HP 438A, DeskJet, and LaserJet are registered trademarks of Hewlett-Packard Company. GPC-7 is a registered trademark of Amphenol Corporation. Microsoft Excel, Notepad, and Windows are trademarks of Microsoft Corporation.

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 computer programs. The drawings, specifications, and information contained herein are the property of Anritsu 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 written 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 this information carefully BEFORE operating the equipment.

Symbols Used in Manuals DANGER WARNING CAUTION
Indicates a very dangerous procedure that could result in serious injury or death if not performed properly. Indicates a hazardous procedure that could result in serious injury or death if not performed properly. Indicates a hazardous procedure or danger that could result in lightto-severe injury, or loss related to equipment malfunction, if proper precautions are not taken.

Safety Symbols Used on Equipment and in Manuals
The following safety symbols are used inside or on the equipment near operation locations to provide information about safety items and operation precautions. Ensure that you clearly understand the meanings of the symbols and take the necessary precautions BEFORE operating the equipment. Some or all of the following five symbols may or may not be used on all Anritsu equipment. In addition, there may be other labels attached to products that are not shown in the diagrams in this manual.

This symbol indicates a prohibited operation. The prohibited operation is indicated symbolically in or near the barred circle. This symbol indicates a compulsory safety precaution. The required operation is indicated symbolically in or near the circle. This symbol indicates warning or caution. The contents are indicated symbolically in or near the triangle. This symbol indicates a note. The contents are described in the box.

These symbols indicate that the marked part should be recycled.

MS462XX MM

SAFETY-1

For Safety
WARNING Always refer to the operation manual when working near locations at which the alert mark, shown on the left, is attached. If the operation, etc., is performed without heeding the advice in the operation manual, there is a risk of personal injury. In addition, the equipment performance may be reduced. Moreover, this alert mark is sometimes used with other marks and descriptions indicating other dangers.

WARNING When supplying AC power to this equipment, connect the accessory 3-pin power cord to a 3-pin grounded power outlet. If a grounded 3-pin outlet is not available, use a conversion adapter and ground the green wire, or connect the frame ground on the rear panel of the equipment to ground. If power is supplied without grounding the equipment, there is a risk of receiving a severe or fatal electric shock.

WARNING This equipment cannot be repaired by the operator. DO NOT attempt to remove the equipment covers or to disassemble internal components. Only qualified service technicians with a knowledge of electrical fire and shock hazards should service this equipment. There are high-voltage parts in this equipment presenting a risk of severe injury or fatal electric shock to untrained personnel. In addition, there is a risk of damage to precision components.

Repair

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

SAFETY-2

MS462XX MM

Table of Contents, Narrative
Chapter 1--General Service Information This chapter familiarizes the user with the basic MS462XX Vector Network Measurement System. Included is information about related manuals, available models and options, preventive maintenance, recommended test equipment, replaceable assembly part numbers, and customer service contact information. Chapter 2--Theory of Operation This chapter provides a brief overview of the functional assemblies and major parts that comprise a typical MS462XX Vector Network Measurement System. It also briefly describes the operation of each major assembly and includes system block diagrams. Chapter 3--Operational Performance Tests This chapter provides general operational tests for all instruments with most of the available options. Chapter 4--System Performance Verification This chapter provides performance verification procedures for all non-C models. Chapter 5--Adjustments This chapter provides calibration procedures. Procedures include 10 MHz calibration, ALC adjustment, Back-end calibration, and Noise Source Internal Through Path characterization. Chapter 6--Troubleshooting This chapter provides information for troubleshooting MS462XX Vector Network Measurement System. The troubleshooting procedures contained in this chapter support fault isolation down to a replaceable subassembly. Chapter 7--Removal and Replacement Procedures This chapter describes how to gain access to all of the major assemblies and major parts for troubleshooting and/or replacement. Appendix A--Connector Care and Handling This appendix provides information on the proper care and handling of RF sensor connectors. Appendix B--Performance Specifications This appendix contains performance specifications. Subject Index

MS462XX MM

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Table of Contents
Chapter 1 General Information
1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 1-10 1-11 1-12 1-13 1-14 SCOPE OF THIS MANUAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 RELATED MANUALS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 MODELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 OPTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 IDENTIFICATION NUMBER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SERVICE POLICY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SPARE PARTS LISTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 ASSEMBLY EXCHANGE PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . 1-7 PREVENTIVE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7 RECOMMENDED TEST EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . 1-7 CONVENTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10 COMPONENT HANDLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11 SERVICE CENTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Chapter 2 Theory of Operation
2-1 2-2 2-3 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 SYSTEM OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 SOURCE MODULE . . . . . . . . . . . . . Digital Interface . . . . . . . . . . . . . Main Oscillator Loops . . . . . . . . . . Offset Oscillator Loops . . . . . . . . . DDS Reference Clock . . . . . . . . . . Bounding Circuitry . . . . . . . . . . . Speed-Up Circuitry . . . . . . . . . . . Frequency Bands and Switched Filters. Heterodyne Oscillator . . . . . . . . . . ALC Circuitry . . . . . . . . . . . . . . Operation Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 2-5 2-5 2-5 2-6 2-6 2-7 2-7 2-7 2-8 2-8

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Table of Contents (Continued)
2-4 RECEIVER MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10 Down Conversion Module . . . . . . . . . . . . . . . . . . . Digital Interface . . . . . . . . . . . . . . . . . . . . . . . . Test Channel Intermediate Frequency Path . . . . . . . . . Reference Channel Intermediate Frequency Path . . . . . . Sampling of the Intermediate Frequency . . . . . . . . . . . ADC Clock Generation/ DSP Communication Port Interface 10 MHz Clock Distribution . . . . . . . . . . . . . . . . . . RF Component Control. . . . . . . . . . . . . . . . . . . . . 2-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10 2-10 2-11 2-12 2-13 2-14 2-14 2-14

FRONT END RF COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15 Test Port Connectors . . . . . . . . . . . . . . . . Switched Frequency Doubler Module . . . . . . . Switched Frequency Tripler Module . . . . . . . Auto-Reversing Module . . . . . . . . . . . . . . Non-Reversing Module . . . . . . . . . . . . . . . Step Attenuator . . . . . . . . . . . . . . . . . . Port Module. . . . . . . . . . . . . . . . . . . . . Port 3 Module. . . . . . . . . . . . . . . . . . . . Low Noise Pre-Amplifier . . . . . . . . . . . . . . Switched Module . . . . . . . . . . . . . . . . . . High Isolation Switch Module . . . . . . . . . . . Receiver Module Configurations. . . . . . . . . . Receiver Module Configurations, MS462XA . . . Receiver Module Configurations, MS462XB . . . Receiver Module Configurations, MS462XC . . . Receiver Module Configurations, MS462XD . . . Option 3--Second Source . . . . . . . . . . . . . Option 4--Noise Figure Measurement Capability Option 6--Third Test Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15 2-15 2-15 2-15 2-16 2-16 2-16 2-16 2-16 2-16 2-16 2-16 2-17 2-17 2-18 2-19 2-20 2-20 2-21 2-21 2-21 2-22 2-23 2-23

2-6

OPTION MODULES . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frequency Translating Group Delay (FTGD) Synthesizer . Frequency Translating Group Delay Receiver . . . . . . . Wideband Noise Figure Receiver . . . . . . . . . . . . . .

2-7 2-8

CENTRAL PROCESSOR MODULE. . . . . . . . . . . . . . . . . . . . . . . . . 2-25 RECEIVER MODULE BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . 2-25

iv

MS462XX MM

Table of Contents (Continued)
Chapter 3 Operational Performance Tests
3-1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 3-9 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 CHECKING THE SERVICE LOG/SELF-TEST . . . . . . . . . . . . . . . . . . . 3-3 VERIFYING OUTPUT POWER ACCURACY . . . . . . . . . . . . . . . . . . . . 3-5 NON-RATIO PARAMETER TEST (MS462XA/C/D) . . . . . . . . . . . . . . . . . 3-7 SYSTEM DYNAMIC RANGE TEST (MS462XA/B/D) . . . . . . . . . . . . . . . 3-10 SYSTEM DYNAMIC RANGE TEST (MS462XC) . . . . . . . . . . . . . . . . . . 3-14 COMPRESSION LEVEL TEST (MS462XC) . . . . . . . . . . . . . . . . . . . . 3-16 RECEIVER MAGNITUDE DISPLAY LINEARITY TEST (MS462XC) . . . . . . 3-19 NOISE FIGURE MEASUREMENT CAPABILITY (OPTION 4) . . . . . . . . . . 3-26 Noise Figure Assurance Check . . . . . . . . . . . . . . . . . . . . . . . . . 3-26 Raw Receiver Noise Figure Check . . . . . . . . . . . . . . . . . . . . . . . . 3-26 NOISE FIGURE MEASUREMENT CONFIDENCE CHECK . . . . . . . . . . . 3-30 FREQUENCY TRANSLATING GROUP DELAY (OPTION 5) . . . . . . . . . . . 3-35 37SF50 PHASE HARMONIC STANDARDS OPERATIONAL CHECK . . . . . . 3-36 Input and Output Return Loss Check . . . . . . . . . . . . . . . . . . . . . . 3-36 3-13 HARMONIC OUTPUT CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-39

3-10 3-11 3-12

Chapter 4 System Performance Verification
4-1 4-2 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 CALIBRATION AND MEASUREMENT CONDITIONS . . . . . . . . . . . . . . 4-4 Standard Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 Special Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 PERFORMANCE VERIFICATION FOR THE MS462XA/B/D MODELS . . . . . . 4-5 2300-482 Software Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 2300-482 Verification Software Overview . . . . . . . . . . . . . . . . . . . . 4-6 VNMS TRACEABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

4-3

4-4

Chapter 5 Adjustments
5-1 5-2 5-3 5-4 5-5 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 RECOMMENDED TEST EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . 5-4 TEST CONDITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 PRE-TEST SETUP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 10 MHz CALIBRATION PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . 5-4 Manual Calibration Procedure: . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

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Table of Contents (Continued)
5-6 5-7 5-8 ALC ADJUSTMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . 5-8 BACK-END ATTENUATOR CALIBRATION (OPTION 4X ONLY) . . . . . . . . 5-10 NOISE SOURCE SIGNAL INTERNAL THROUGH PATH CHARACTERIZATION (OPTION 4X ONLY) . . . . . . . . . . . . . . . . . . . . 5-11

Chapter 6 Troubleshooting
6-1 6-2 6-3 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 SELF TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 TROUBLESHOOTING TOOLS FOR THE CPU MODULE SRAM . . . . . . . . . . . . . . . . . . . . . . . . . . SRAM DISK . . . . . . . . . . . . . . . . . . . . . . . FLASH MEMORY . . . . . . . . . . . . . . . . . . . . EXTENDED FLASH MEMORY . . . . . . . . . . . . DRAM . . . . . . . . . . . . . . . . . . . . . . . . . . GRAPHICS VRAM . . . . . . . . . . . . . . . . . . . GRAPHICS DRAM . . . . . . . . . . . . . . . . . . . DSP SRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 6-6 6-6 6-6 6-6 6-7 6-7 6-7 6-7

6-4

HARDWARE TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . 6-8 CPU MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8 SOURCE MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9 HET OSCILLATOR VOLTAGE . . . . . . . . . . . . . . . . . . . . . . . . . 6-11 SOURCE 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12 SOURCE 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12 LO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12 AUTO LEVEL CONTROL (ALC) . . . . . . . . . . . . . . . . . . . . . . . . 6-13 RECEIVER MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 NOISE SOURCE POWER SUPPLY. . . . . . . . . . . . . . . . . . . . . . . 6-21 POWER DISTRIBUTION UNIT. . . . . . . . . . . . . . . . . . . . . . . . . 6-21 FRONT PANEL ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22

6-5 6-6 6-7 6-8

SOFTWARE PROBLEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23 MEASUREMENT QUALITY PROBLEM . . . . . . . . . . . . . . . . . . . . . . 6-23 NOISE FIGURE MEASUREMENT PROBLEM . . . . . . . . . . . . . . . . . . 6-24 FREQUENCY TRANSLATING GROUP DELAY MEASUREMENT . . . . . . . 6-27

vi

MS462XX MM

Table of Contents (Continued)
Chapter 7 Removal and Replacement Procedures
7-1 7-2 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3 FRONT PANEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4 Floppy Disk Drive Assembly LCD Assembly . . . . . . . . LCD Backlight Driver PCB . Interface PCB . . . . . . . . Backlight Fluorescent Lamp 7-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6 7-6 7-7 7-7 7-8

POWER DISTRIBUTION UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9 PDU Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11

7-4

CPU ASSEMBLY . . . . . . . System Firmware PROM CPU Heatsink with Fan . Lithium Battery . . . . .

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7-12 7-14 7-15 7-15

7-5 7-6 7-7 7-8

RECEIVER MODULE ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . 7-18 TEST PORT CONNECTOR AND PORT MODULE . . . . . . . . . . . . . . . . 7-20 OPTION AND SOURCE MODULES . . . . . . . . . . . . . . . . . . . . . . . . 7-21 BACKPLANE PCB ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23

Appendix A Connector Care and Handling
A-1 A-2 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3 CONNECTOR CARE AND HANDLING . . . . . . . . . . . Beware of Destructive Pin Depth of Mating Connectors. Avoid Over-Torquing Connectors . . . . . . . . . . . . . Cleaning Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3 A-3 A-4 A-5

Appendix B Performance Specifications Subject Index

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Chapter 1 General Information Table of Contents
Chapter 1 General Information
1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 1-10 1-11 1-12 1-13 1-14 SCOPE OF THIS MANUAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 RELATED MANUALS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 MODELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 OPTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 IDENTIFICATION NUMBER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SERVICE POLICY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SPARE PARTS LISTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 ASSEMBLY EXCHANGE PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . 1-7 PREVENTIVE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7 RECOMMENDED TEST EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . 1-7 CONVENTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10 COMPONENT HANDLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11 SERVICE CENTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Figure 1-1. MS462XX Vector Network Measurement System

1-2

MS462XX MM

Chapter 1 General Information
1-1
SCOPE OF THIS MANUAL This manual provides general information, performance verification, calibration, theory, and service information for the Anritsu MS462XX Vector Network Measurement System. The MS462XX Vector Network Measurement System is shown in Figure 1-1 (facing page). This chapter provides information to familiarize the user with the basic MS462XX Vector Network Measurement System. Included is information about related manuals, and the available models and options. This manual is one of a five manual set consisting of this Maintenance Manual, the MS462XX Operation Manual (Anritsu part number 10410-00203), the MS462XX Programming Manual (10410-00204), the MS462XX Scorpion Measurement Guide (10410-00213), and the MS462XX GPIB Quick Reference Guide (10410-00206). With twelve basic models and a number of powerful options to choose from, the MS462XX can be configured to address many measurement requirements. The following models are available as platforms:
Model Number
MS4622A MS4622B MS4622C MS4622D MS4623A MS4623B MS4623C MS4623D MS4624A MS4624B MS4624C MS4624D

1-2 1-3

INTRODUCTION

RELATED MANUALS

1-4

MODELS

Frequency Range
10 MHz to 3 GHz 10 MHz to 3 GHz 10 MHz to 3 GHz 10 MHz to 3 GHz 10 MHz to 6 GHz 10 MHz to 6 GHz 10 MHz to 6 GHz 10 MHz to 6 GHz 10 MHz to 9 GHz 10 MHz to 9 GHz 10 MHz to 9 GHz 10 MHz to 9 GHz

Configuration
Transmission/Reflection Full Reversing Direct Receiver Access Balanced/Differential Transmission/Reflection Full Reversing Direct Receiver Access Balanced/Differential Transmission/Reflection Full Reversing Direct Receiver Access Balanced/Differential

The Transmission/Reflection models offer an economical solution for the manufacturing line that requires only S11 and S21 measurements without sacrificing the excellent performance of the Full Reversing models.

MS462XX MM

1-3

OPTIONS

GENERAL INFORMATION

1-5

OPTIONS

The following options are easily added to the MS462XX platform for increased measurement capabilities:
Option Number
2 3A 3B 3C 3D 3E 3F 4, 4D, 4F 4B, 4E, 4G 5 6 7 8 10 11 13 24

Description
Time Domain Second Internal Source4 Second Internal Source4 Second Internal Source5 Second Internal Source5 Second Internal Source7 Second Internal Source7 Noise Figure1 Noise Figure6 Frequency Translating Group Delay Third Test Port3 T/R Step Attenuator Harmonic Measurement AutoCal Control Test Port Connector Intermodulation Distortion Processing Upgrade

Availability
All Models 3 GHz Source B Models 6 GHz Source B Models 3 GHz Source C Models 6 GHz Source C Models 9 Ghz Source D Models 9 Ghz Source C Models B, C and D Models Only B, C and D Models Only B and C Models Only B and C Models Only A Models Only All Models All Models All Models 2 All Models B and C Models Only

1. 50 MHz to 3 GHz 2. Standard Connector is N-female, No cost option for 3.5 mm (male), 3.5 mm (female), N-Male, or GPC-7. 3. Requires external source, 68XXX Synthesizer 4. Third test port included 5. Third output port included 6. 50 MHz to 6 Ghz 7. Third and Fourth output port included

1-6 1-7

IDENTIFICATION NUMBER

The MS462XX Vector Network Measurement System's ID number is affixed to the rear panel. Please use the complete ID number when ordering parts or corresponding with the Anritsu Customer Service department. The MS462XX Vector Network Measurement System's modular design, extensive built-in diagnostics, and automated service tools are designed to support fast exchange of functional assembly level repairs. Failed assemblies are not field repairable. Once an assembly is found to be faulty, it should be returned to an authorized Anritsu Service Center (Table 1-4) for exchange.

SERVICE POLICY

1-4

MS462XX MM

GENERAL INFORMATION

SPARE PARTS LISTING

1-8

SPARE PARTS LISTING

The assemblies and spare parts listed in Table 1-1 through Table 1-3 are available for the MS462XX Vector Network Measurement System. Refer to Chapter 7 for removal and replacement procedures. Contact your nearest Anritsu Customer Service or Sales Center for price and availability information (Table 1-4).
Table 1-1. Assemblies Common to All MS462XX Instruments Description
Main Source Module Optional Source Module CPU Board CPU Heatsink with Fan CPU Boot PROM Lithium Battery (for CPU) Receiver PCB Power Supply (PDU) Entire Power Supply Fan Assembly Power Supply Fuse Option Module Assembly Floppy Drive LCD Display LCD Backlight Driver PCB LCD Window (Plastic shield) Lamp for Sharp LQ9D340 LCD Chassis (Instrument frame) Front Panel PCB, Keypad, Knob for 2 or 3 Ports Front Panel PCB, Keypad, Knob for 4 Ports Backplane PCB Test Port Connector (N Female) Test Port Connector (N Male) Test Port Connector (GPC-7) Test Port Connector (3.5mm Male) Test Port Connector (3.5mm F) Operating Software Boot Utility Software Handle, Standard (Right) Handle, Standard (Left) 52392 52393 See Table 1-3 650-34 58-1638 633-25 See Table 1-3 ND55521 ND49520 631-90 ND56500 ND50711 15-100 2000-770 48177 632-55 D43325 ND48996 ND58272 48522-4 B45259 B45261 B47086 B47088 B47087 2300-244 2300-246 D37169-4 D37168-4

Part Number

MS462XX MM

1-5

SPARE PARTS LISTING

GENERAL INFORMATION

Table 1-2. Replaceable Internal Microwave Components Description
AutoReverse Module (9 GHz units) AutoReverse Module (3 and 6 GHz units) Source Doubler Module (3 and 6 GHz units) Down Converter Module (3 and 6 GHz units) Down Converter Module (9 GHz units) Port 3 Module (all units) Port 1, 2 Module (all units) Tripler Module (9 GHz units) Hi Iso Switch (3 and 6 GHz units) Hi Iso Switch (9 GHz units) Non-Reversing Module (all units) Low Noise Amp for Opt. 4 (3 and 6 GHz units) Switch Module for Opt. 4 (3 and 6 GHz units) 54530 44666 28875 29830 54610 44668 46720 56630 53077 60261 49983 53300 46718

Part Number

Table 1-3. Model-Specific Exchange Kits Model
MS4622A MS4622B MS4622C MS4622D (without Opt.4) MS4622D (with Opt.4)

Receiver PCB Exchange Kit
ND49524 ND49524 ND53277 ND57968 ND60706

CPU Exchange Kit
ND55522 ND55522 * ND55522 * ND57970 ND57970

MS4623A MS4623B MS4623C MS4623D (without Opt.4) MS4623D (with Opt.4)

ND49524 ND49524 ND53277 ND57968 ND60706

ND55522 ND55522 * ND55522 * ND57970 ND57970

MS4624A MS4624B MS4624C MS4624D (without Opt.4) MS4624D (with Opt.4)

ND55524 ND55524 ND60331 ND57968 ND60706

ND55522 * ND55522 * ND55522 * ND57970 ND57970

* Use ND55522 if Option 24 is not installed. Use ND57970 if Option 24 is installed.

1-6

MS462XX MM

GENERAL INFORMATION

ASSEMBLY EXCHANGE PROGRAM

1-9

ASSEMBLY EXCHANGE PROGRAM

Anritsu maintains an exchange assembly program for selected MS462XX subassemblies and RF components. If a malfunction occurs in one of these subassemblies, the defective unit can be exchanged. All exchange subassemblies or RF components are warrantied for 90 days from the date of shipment, or the balance of the original equipment warranty, whichever is longer. A hard copy or saved to disk copy of the instrument Service Log must accompany all exchange modules. To access the Service Log, press the Utility front panel key, followed by the SERVICE LOG menu soft key. Select either PRINT LOG or SAVE LOG TO DISK. NOTE When sending an assembly to the factory for exchange, a copy of the Service Log must accompany the assembly. Exchange prices can only be offered if the Service Log data is included with the assembly to be exchanged. Please have the exact model number and serial number of your unit available when requesting this service, as the information about your system is filed according to the instrument model and serial number. For more information about the assembly exchange program, contact your local sales representative or call your local Anritsu Service Center. Refer to Table 1-4 for a list of current Anritsu Service Centers.

1-10

PREVENTIVE MAINTENANCE

The MS462XX CPU module contains a battery-backed memory/real time clock chip (BBRAM) and a static memory (SRAM) backup battery. The BBRAM chip has a rated life span of 10 years, and the SRAM backup battery has a worst-case life span of two years at 25°C when the instrument is stored (always off). Exposure to temperatures above 60°C will dramtically reduce this worst-case life span. The SRAM backup battery should be replaced every three years. For instruments with serial number 995299 and below, the LCD (Anritsu part number 15-92) contains a backlight flourescent lamp that has a rated 10,000 hour life span. For instruments with serial number 000101 and above, the LCD (Anritsu part number 15-100) contains a backlight flourescent lamp that has a rated 50,000 hour life span. Both the SRAM backup battery and backlight lamp should be replaced periodically per the procedures in Chapter 7.

1-11

RECOMMENDED TEST EQUIPMENT

The following test equipment is recommended for servicing the MS462XX Vector Network Measurement System. The list is a suggestion and by no means comprises a comprehensive list of all equipment necessary to service this system. Functionally equivalent equipment may be substituted for the recommended manufacturer or model as long as the critical specifications are met. Inclusion on this list does not constitute an endorsement or suitability of purpose of any particular equipment or manufacturer. The Application Code column of the following table represents when or where the specified equipment would be used:

MS462XX MM

1-7

RECOMMENDED TEST EQUIPMENT

GENERAL INFORMATION

Instrument
Computer or Controller

Critical Specifications
Personal Computer: Pentium class processor, Win 95 (16 MB RAM min.) GPIB Interface

Recommended Manufacturer or Model
Any Desktop PC:

Application Code
O, P

National Instruments PCI-GPIB or AT-GPIB/TNT (plug-and-play) Notebook PC: National Instruments PCMCIA-GPIB

Performance Verification Software GPIB Cable RF/Microwave Cable Printer Port Test Throughline (3 each) DC to 6 GHz, K or 3.5 mm connectors (male or female)

Anritsu 2300-482

P

Anritsu 2100-X Any

O, P, A O

Anritsu ND51900 Anritsu 3670A50-2, 3670K50-2, 3670N50-2, 3670NN50-2 Anritsu 3753LF/3753R with Option 1 and 3 Anritsu 3750LF/3750R with Option 1 and 3 Anritsu 3751LF/3751R with Option 3 Anritsu 23NF50 Anritsu 23N50 Anritsu 23LF50 Anritsu 23L50 Anritsu 23A50 Anritsu 3663LF/3663R Anritsu 3666LF/3666R Anritsu 3667LF/3667R Anritsu MF2412B or EIP Microwave, Inc., Model 548B

O O, P

N test port connector 3.5 mm test port connector GPC-7 test port connector Short Two each of: N male test port N female test port 3.5mm male test port 3.5mm female test port GPC-7 test port N test port connector 3.5mm test port connector GPC-7 test port connector Frequency: 1 to 20 GHz Input Impedance: 50 W Frequency Stability: -7 Temperature = 1x10

O, P O, P O, P O

Calibration Kit

Verification Kit

P

Frequency Counter

A

1-8

MS462XX MM

GENERAL INFORMATION

RECOMMENDED TEST EQUIPMENT

Instrument
Power Meter and Sensor

Critical Specifications
Power Meter: Power Range 70 to +20 dBm GPIB controllable Power Sensor: Frequency Range 10 MHz to 18 GHz Power Range 70 to +20 dBm

Recommended Manufacturer or Model
Anritsu ML2430A Series

Application Code
O, A, P

Anritsu MA2472A

Digital Multimeter Oscilloscope

Resolution: 4 ½ digits DC Accuracy: 0.1 % AC Accuracy: 0.1 % Bandwidth : DC to 100 MHz Sensitivity: 2 mV Horiz. Sensitivity: 50 ns/division

Any

T

Tektronix Inc., Model 2445

T

Power Supply Power Amplifier Noise Source Step Attenuator Attenuator

Voltage: +12V Current: 100 mA min. Gain: 10 dB min. Noise Figure: 5.5 dB typical 15 dB ENR With calibration data at 50 MHz 10 dB

Any Mini-Circuit ZJL-4G (4 GHz) APN:60-242 ZJL-6G (6 GHz) APN:60-234 Anritsu NC346B Anritsu MN510C Anritsu 43KC-10

O O

O P P

Application Codes: A = Adjustment / Internal Hardware Calibration O = Operational Testing P = Performance Verification T = Troubleshooting

MS462XX MM

1-9

CONVENTIONS

GENERAL INFORMATION

1-12

CONVENTIONS

Throughout this manual, path names may be used to represent the keystrokes for a desired action or procedure. The path name begins with a front panel key selection, followed by additional front panel or soft key selections, each separated by a forward slash (/). Front panel key names and soft keys are presented in the manual as they are on the system, that is, in initial caps or all uppercase letters as appropriate. For example, the following path name representation displays the system model number, serial number, current software version, and installed options: Utility/INSTRUMENT STATE PARAMETERS/SYSTEM Following the path above, the user would press the Utility front panel key, followed by the INSTRUMENT STATE PARAMETERS soft key, then the SYSTEM soft key to display the system information. Individual steps within a procedure may also be presented as sequentially numbered steps for clarity. Again, front panel key names and soft keys are presented in the manual as they are on the system. For example, the following procedure displays the system model number, serial number, current software version, and installed options: 1. 2. Press the Utility front panel key. Select the menu soft keys as follows: INSTRUMENT STATE PARAMETERS SYSTEM

1-10

MS462XX MM

GENERAL INFORMATION

COMPONENT HANDLING

1-13

COMPONENT HANDLING

The MS462XX series contains components that can be damaged by static electricity. The following figures illustrate the precautions that should be followed when handling static-sensitive subassemblies and components. If followed, these precautions will minimize the possibilities of staticshock damage to these items. NOTE Use of a grounded wrist strap when removing and/or replacing subassemblies or parts is strongly recommended.

1. Do not touch exposed contacts on any static sensitive component.

2. Do not slide static sensitive component across any surface.

3. Do not handle static sensitive components in areas where the floor or work surface covering is capable of generating a static charge.

4. Wear a static-discharge wristband when working with static sensitive components.

5. Label all static sensitive devices.

6. Keep component leads shorted together whenever possible.

MS462XX MM

1-11

COMPONENT HANDLING

GENERAL INFORMATION

7. Handle PCBs only by their edges. Do not handle by the edge connectors.

8. Lift & handle solid state devices by their bodies--never by their leads.

9. Transport and store PCBs and other static sensitive devices in staticshielded containers.

ADDITIONAL PRECAUTIONS Keep work spaces clean and free of any objects capable of holding or storing a static charge. Connect soldering tools to an earth ground. Use only special anti-static suction or wick-type desoldering tools.

CAUTION Electrostatic Discharge (ESD) can damage the highly sensitive circuits in the MS462XX VNMS. ESD is most likely to occur as test devices are being connected to, or disconnected from, the instrument's front and rear panel ports and connectors. You can protect the instrument and test devices by wearing a static-discharge wristband. Alternatively, you can ground yourself to discharge any static charge by touching the outer chassis of the grounded instrument before touching the intrument's front and rear panel ports and connectors. Avoid touching the test port center conductors unless you are properly grounded and have eliminated the possibility of static discharge. Repair of damage that is found to be caused by ESD is not covered under warranty.

1-12

MS462XX MM

GENERAL INFORMATION

SERVICE CENTERS

1-14

SERVICE CENTERS
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

Table 1-4. 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: (973) 227-8999 1-800-ANRITSU FAX: 973-575-0092 ANRITSU COMPANY 1155 E. Collins Blvd Richardson, TX 75081 Telephone: 1-800-ANRITSU FAX: 972-671-1877

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

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

SINGAPORE
ANRITSU (SINGAPORE) PTE LTD. 10, Hoe Chiang Road #07-01/02 Keppel Towers Singapore 089315 Telephone: 6-282-2400 FAX: 6-282-2533

INDIA
MEERA AGENCIES PVT. LTD. 23 Community Centre Zamroodpur, Kailash Colony Extension, New Delhi, India 110 048 Phone: 011-2-6442700/6442800 FAX : 011-2-644250023

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

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

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

SWEDEN
ANRITSU AB Borgafjordsgatan 13 164 40 KISTA, Sweden Telephone: +46-8-53470700 FAX: +46-8-53470730

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

ITALY
ANRITSU Sp.A Roma Office Via E. Vittorini, 129 00144 Roma EUR Telephone: (06) 50-99-711 FAX: (06) 50-22-425

TAIWAN
ANRITSU CO., INC. 7F, No. 316, Section 1 NeiHu Road Taipei, Taiwan, R.O.C. Telephone: 886-2-8751-1816 FAX: 886-2-8751-2126

CANADA
ANRITSU INSTRUMENTS LTD. 700 Silver Seven Road, Suite 120 Kanata, Ontario K2V 1C3 Telephone: (613) 591-2003 FAX: (613) 591-1006

KOREA
ANRITSU CORPORATION LTD. 8F Hyunjuk Building, 832-41 Yeoksam Dong, Kangnam-Ku Seoul, South Korea 135-080 Telephone: 02-553-6603 FAX: 02-553-6605

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

CHINA
ANRITSU ELECTRONICS (SHANGHAI) CO. LTD. 2F, Rm B, 52 Section Factory Building No. 516 Fu Te Rd (N) Shanghai 200131 P.R. China Telephone:21-58680226, 58680227, 58680228 FAX: 21-58680588

MS462XX MM

1-13/1-14

Chapter 2 Theory of Operation Table of Contents
2-1 2-2 2-3 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 SYSTEM OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 SOURCE MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 Digital Interface . . . . . . . . . . . . . Main Oscillator Loops . . . . . . . . . . Offset Oscillator Loops . . . . . . . . . DDS Reference Clock . . . . . . . . . . Bounding Circuitry . . . . . . . . . . . Speed-Up Circuitry . . . . . . . . . . . Frequency Bands and Switched Filters. Heterodyne Oscillator . . . . . . . . . . ALC Circuitry . . . . . . . . . . . . . . Operation Modes. . . . . . . . . . . . . 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 2-5 2-5 2-6 2-6 2-7 2-7 2-7 2-8 2-8

RECEIVER MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10 Down Conversion Module . . . . . . . . . . . . . . . . . . . Digital Interface . . . . . . . . . . . . . . . . . . . . . . . . Test Channel Intermediate Frequency Path . . . . . . . . . Reference Channel Intermediate Frequency Path . . . . . . Sampling of the Intermediate Frequency . . . . . . . . . . . ADC Clock Generation/ DSP Communication Port Interface 10 MHz Clock Distribution . . . . . . . . . . . . . . . . . . RF Component Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10 2-10 2-11 2-12 2-13 2-14 2-14 2-14

Table of Contents (Continued)
2-5 FRONT END RF COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15 Test Port Connectors . . . . . . . . . . . . . . . . Switched Frequency Doubler Module . . . . . . . Switched Frequency Tripler Module . . . . . . . Auto-Reversing Module . . . . . . . . . . . . . . Non-Reversing Module . . . . . . . . . . . . . . . Step Attenuator . . . . . . . . . . . . . . . . . . Port Module. . . . . . . . . . . . . . . . . . . . . Port 3 Module. . . . . . . . . . . . . . . . . . . . Low Noise Pre-Amplifier . . . . . . . . . . . . . . Switched Module . . . . . . . . . . . . . . . . . . High Isolation Switch Module . . . . . . . . . . . Receiver Module Configurations. . . . . . . . . . Receiver Module Configurations, MS462XA . . . Receiver Module Configurations, MS462XB . . . Receiver Module Configurations, MS462XC . . . Receiver Module Configurations, MS462XD . . . Option 3--Second Source . . . . . . . . . . . . . Option 4--Noise Figure Measurement Capability Option 6--Third Test Port . . . . . . . . . . . . . 2-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15 2-15 2-15 2-15 2-16 2-16 2-16 2-16 2-16 2-16 2-16 2-16 2-17 2-17 2-18 2-19 2-20 2-20 2-21

OPTION MODULES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frequency Translating Group Delay (FTGD) Synthesizer . Frequency Translating Group Delay Receiver . . . . . . . Wideband Noise Figure Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21 2-22 2-23 2-23

2-7 2-8

CENTRAL PROCESSOR MODULE. . . . . . . . . . . . . . . . . . . . . . . . . 2-25 RECEIVER MODULE BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . 2-25

2-2

MS462XX MM

Chapter 2 Theory of Operation
2-1
INTRODUCTION This chapter provides a brief overview of the functional assemblies and major parts that comprise a typical MS462XX Vector Network Measurement System. It also briefly describes the operation of each major assembly. MS462XA/B Series Vector Network Measurement Systems are ratio measurement systems used to measure complex vector signal characteristics of devices and systems in the 10 MHz to 9 GHz range. They also incorporate special measurement capabilities such as Noise Figure measurement, Intermodulated Distortion measurement, and more. The MS462XC Series Vector Network Measurement Systems are configured as Direct Access Receivers for antenna, frequency conversion, and multiple output device measurements in the 10 MHz to 9 GHz range. They also maintain the ability to measure all four S-parameters with the addition of a reflectometer setup at the front end of the receiver. The MS462XD Series Vector Network Measurement Systems are used to measure complex vector signal characteristics of multiport balanced/differential devices and systems in the 10 MHz to 9 GHz range. The MS462XX performs complex vector signal measurements by sourcing a stimulus signal to the Device Under Test (DUT) connected to the front panel Port 1, Port 2, Port 3 (optional for MS462XB), or Port 4 (for MS462XD) connectors. It simultaneously measures the DUT response, which consists of reflected or transmitted (attenuated or amplified) signals at the connectors of the DUT. The reflected or transmitted signal(s) and a sample of the stimulus signal are down converted to 125 kHz intermediate frequency (IF) signals. These IF signals are then converted into digital information and sent to the Central Processor Module where the digital information is processed by a Digital Signal Processor (DSP) using Single Frequency Digital Fourier Transfer to determine the magnitude and phase of the signal being measured. The information is then normalized for the desired S-parameter and presented to the user via the front panel color LCD display. The display information is also available on the rear panel VGA Out connector for use with an external VGA monitor. The normalized measurement information is also available on the rear panel Printer Out connector and Dedicated GPIB connector for use with an external printer and plotter respectively.

2-2

SYSTEM OVERVIEW

MS462XX MM

2-3

SOURCE MODULE

THEORY OF OPERATION

A front panel keypad, rotary knob, and IBM compatible keyboard interface provide user interaction with the MS462XX Central Processor Module. The system is also equipped with a floppy disk drive and non-volatile internal memory for storage and retrieval of data and front panel setup information. The MS462XX implements an IEEE 488.2 GPIB interface that allows an externally connected instrument controller to control the MS462XX system in the "Remote-Only" mode. All MS462XX measurement and input/output operations may be controlled remotely in this mode. An internal service log stores a record of system failures, data about the failures, and other key system service information. The service log is implemented using an internal battery-backed SRAM memory.

2-3

SOURCE MODULE

There are two source modules for the MS462XX Series Vector Network Measurement System. The Source/Local Oscillator Module is standard on all models and an Optional Source Module is installed when using 3- and 4-port configurations with an active internal source. The Source/Local Oscillator module generates the primary source RF and local oscillator output. This module contains the phase lock circuitry for the oscillator's circuitry to generate different output frequency bands covering 10 MHz to 3000 MHz, and banks of switched filter sections. The source output level is controllable through an ALC loop, whereas the Local Oscillator output level is fixed. In addition to the Source and Local Oscillator RF outputs, this module also provides Common Offset and Heterodyne VCO signals used by the optional second source. The optional Source module generates the optional source RF output. This module contains the phase lock circuitry for the oscillator's circuitry to generate different output frequency bands spanning 10 MHz to 3000 MHz, and banks of switched filter sections. The source output level is controllable through an ALC loop. The module receives the Common Offset and Heterodyne VCO signals from the Primary Source/Local Oscillator Number modules. While both modules are similar, the Source/ Local Oscillator module is a fully laden assembly, while the optional Source module contains only the circuitry for the optional source output. Each module has a separate PCB assembly, but both use a common housing. Typical RF output specifications for the modules are:
RF Output Frequency Range: Unleveled Source Port Power Level: LO Port Power Level: RF Output Frequency Range: Heterodyne Output Power Level: Common Offset Power Level: 10 MHz to 3 GHz 27 dBm Max., 16 dBm Min. 12 dBm Max., 1 dBm Min. 800 MHz to 1600 MHz 4 dBm Max., 3 dBm Min. 7 dBm Max., 1 dBm Min.

2-4

MS462XX MM

THEORY OF OPERATION

SOURCE MODULE

The internal ALC level loop allows for a leveled range of 11 dBm to +20 dBm out of the Source RF port. The Local Oscillator is not used on the optional Source module. All frequency loops are phase locked to the internal 10 MHz reference oscillator in the MS462XX. NOTE Six gigahertz instruments use a Switched Doubler module immediately following the source(s). Nine gigahertz instruments use a Switched Tripler module immediately following the source(s). The doublers or triplers are installed on the Receiver PCB assembly. Digital Interface All modules in the instrument share the same bus connections to the microprocessor via the motherboard. The common data and address bus consists of 16 data bits, 5 address lines, and 5 board select lines. Within the Source/LO module, the incoming address and board select lines are decoded to direct data between the common bus and internal module latches. Transceivers are used to buffer the common data bus from an internal data bus. When a latch located on the module is addressed, the transceivers will enable the transfer of data to or from the internal data bus. The Source and LO RF outputs are both generated by voltage controlled oscillators (VCOs) that nominally cover 800 to 1600 MHz. The outputs of the VCOs are processed to ultimately produce the final outputs of the module. Additionally, the outputs of the main oscillators are sampled and fed back, in order to be phase-locked to the system reference 10 MHz. The phase locking circuitry for the Source and LO VCOs are essentially identical in their implementation. When phase locking the main oscillator, the VCO is mixed with an offset oscillator to produce a lower frequency signal. This mixed down signal is input to a phase detector and is compared to a signal produced by a Direct Digital Synthesis (DDS) IC. The DDS has better than 1 Hz resolution, which is transferred to the main VCO. The phase detector output is fed into a loop filter, which supplies the tuning voltage (0.5 to 20 volts) to the VCO. Offset Oscillator Loops The offset oscillator used by the source and the LO are also 800 to 1600 MHz VCOs. The VCOs are also phase-locked to the system's 10 MHz reference (fref) using a PLL IC. The PLL IC integrates two programmable dividers, a prescaler and a phase/frequency detector. The PLL IC operates in frequency ranges up to 2.5 GHz. The circuitry used to lock up the source offset oscillator is reproduced for the LO offset VCO. The outputs of the two dividers are programmed to 625 kHz. The phase detector issues a correction current pulse using the internal charge pump. The loop amplifier integrates current pulses from the PLL IC. The tuning sensitivity at the VCO input is approximately 50 MHz/V.

Main Oscillator Loops

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SOURCE MODULE

THEORY OF OPERATION

The loop amplifier has a gain of 4; therefore, the sensitivity at the PLL IC output is very high. Thus, any noise injected at this point has noticeable affects on the output noise characteristics. DDS Reference Clock In order to generate accurate DDS frequencies, an accurate reference clock must be provided to the two DDS ICs. The 32 bits of the DDS frequency register allow the minimum output resolution of Fclk divided by 232. By phase locking the DDS reference clock VCXO to 26.8435456 MHz, the resulting minimum resolution is 0.00625 Hz. To get such a precision frequency from the VCXO, it is phase-locked to the system's 10 MHz reference. A third DDS IC, using the VCXO as its clock, is programmed to output 100 kHz. The system reference is divided down to 100 kHz and is compared against the DDS output. Only when the clock is exactly 26.8435456 MHz will the programmed DDS produce a phase locked 100 kHz. The phase detector feeds back to the VCXO tuning line to precisely tune the clock frequency. Bounding Circuitry Bounding is a term for the circuitry that is used to ensure that the VCOs are kept within their range and that the correct frequency is generated. The mixing of the main and offset signals produces an additive as well as the desired subtractive product. Therefore, there is the potential that the main oscillator loops will try to lock on to the wrong signal. To prevent locking on the wrong side, additional PLL ICs are wrapped around the main loop phase detector as bounding circuits. The proper polarity in the loop requires that the main oscillator always be lower in frequency than the offset oscillator. The upper bound PLL is programmed for the offset VCO frequency. When the main VCO goes higher in frequency than the offset VCO, a correction pulse is generated that is fed into the main oscillator loop. This magnitude of the correction pulse is large enough to push the main VCO to the correct side. In addition to being prevented from swinging too high, the main VCO must also be bounded on the low end. For lower main VCO frequencies, the difference frequency increases. However, the mixer has a limited bandwidth. When the bandwidth is exceeded, the output response drops off and it will seem as if the main VCO is too high in frequency, instead of too low. Once again, positive feedback would result. A lower bound PLL will issue a correction pulse to push the main VCO higher in frequency when the bound is exceeded. Both the source and the LO sides incorporate bounding circuits. When the main VCO is within an acceptable range, there is no contribution from the bounding circuits. The PLL ICs used for the bounding circuits are the same components used in the offset VCO loops.

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THEORY OF OPERATION

SOURCE MODULE

Speed-Up Circuitry

In addition to the phase-lock and bounding circuitry, there is also circuitry to help speed the locking of the loop. The settling time of the main loop and its phase detector is very slow. Frequency lock detect circuitry emits pulses to help get the source main VCO locked on frequency quicker. Once on frequency, the speed-up circuit's contribution drops out and the normal phase lock circuitry locks up the loop the rest of the way. In this way, the loop locking occurs more rapidly, but the stability of the loop is not compromised. However, for this speedup to work, the polarity of the loop must be correct. If on the wrong side, then the speedup circuitry only acts to push the VCO even farther off, even faster. Thus a hierarchy of control must be established. The bounding correction circuits must be strong enough to counter the contribution of the speedup circuits, but should not be so strong that the loop ends up banging back and forth between its two extremes.

Frequency Bands and Switched Filters

Although the main oscillator produces an output of 800 to 1600 MHz only, the module output frequency covers 10 MHz to 3 GHz. There are four distinct bands of operation to achieve the desired frequency range. If the desired output frequency is between 10 to 400 MHz, the circuit is in the heterodyne mode. The VCO output is mixed with a heterodyne oscillator (typically 1200 MHz). Passing the VCO output through a divide-by-two circuit produces frequencies between 400 to 800 MHz. For 800 to 1600 MHz, the VCO signal passes directly. To achieve 1600 to 3000 MHz, a doubler is used. To improve harmonics and spurious performance, output signals are passed through switched filter sections. A given frequency mode (Heterodyne, divide-by-two, through, or multiply-by-two) may have one or more switched filter band sections. The switching for the frequency generation modes is combined with the control for the switched filter section.

Heterodyne Oscillator

In the heterodyne mode, a heterodyne oscillator is used to mix with the main VCO outputs of the source and LO to generate frequencies less than 400 MHz. This VCO is the same type as that used for the main and offset loops. The VCO has an 800 to 1600 MHz range, but will typically be tuned to 1200 MHz. The main VCO is tuned higher than the fixed heterodyne oscillator, so that positive steps in system frequency will correspond to positive steps in the main VCO. To avoid mixing spurs, the heterodyne VCO is allowed to step down as far as 900 MHz. The circuitry for the phase-locking of this heterodyne oscillator is similar to the offset VCO locking. The heterodyne VCO signal is also passed along out of the module to be supplied to the optional source for use in its heterodyne mode.

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SOURCE MODULE

THEORY OF OPERATION

ALC Circuitry

The source side differs from the LO side primarily in its ability to have controllable output power. The feedback from a level detector controls the level of the source output. The level of the signal can be controlled over a 20 dB range. In the ALC circuitry, a DAC is set to a calibrated value for a desired power level. The ALC loop then adjusts the level of the source output until the detector output matches the reference voltage. A shaper circuit compensates for the non-linear characteristics of the modulator and doubler. Once placed into a system, the Source/LO Module may be calibrated for leveled power out of the port. In general, the Power Level DAC is stepped while the Source is tuned to a fixed frequency. The port output level is measured with a power meter. The power level at the port is dependent not only on the source output power itself, but also upon the losses through various components in the RF deck. The results are then used to curve-fit an equation that relates DAC values to port power. For a 3 GHz system, the measurements are performed at 1 GHz. If the system is a 6 GHz unit, the measurements are performed at both 1 GHz and 4 GHz. The power curve did not change much with frequency, only the offsets. Therefore, the same curve-fit equations could be used with a correction for the different offsets at various frequencies. The curve-fit equation calculated using 1 GHz data is applied for system frequencies less than 3 GHz. The 4 GHz curve-fit equation is used in the doubler band (i.e. frequencies greater than 3 GHz). The power DAC is set to a 0 dBm port power using the appropriate curve-fit equation, then the resulting error offset is measured. The offsets for different frequency steps are stored in a table and intermediary frequencies are interpolated. Additionally, a shaper DAC calibration is performed when the system is a 6 GHz unit. The shaper DAC is in place to help compensate for changes in the doubler characteristics. At band switch points, the source takes longer to settle. During the settling period, there is a lack of RF signal to the ALC detector diode, thus the ALC circuitry will set the output power higher. Therefore, the ALC is level-dipped at band switch points to prevent large power spikes from hitting the DUT during these transition periods. The level-dip is performed by switching a fixed voltage into the loop.

Operation Modes

There are two operation modes:
Common Traditionally, the source and LO output signals are generated Offset Mode independently. An alternative mode of operation is possible

where the LO offset VCO also locks up the source loop. The source offset VCO is disabled in this mode. The DDS outputs on the two sections then make up the frequency difference between the two outputs. Sharing a common offset VCO allows the two signal sources to better track each other. The resulting IF has better phase noise because much of the offset VCO noise is ratioed out.

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MS462XX MM

THEORY OF OPERATION

SOURCE MODULE

To make accurate measurements, the IF must be settled before the Digital Signal Processing (DSP) is triggered. When operating in common offset mode, the IF settles faster. In fact, even though the offset VCO (and therefore the main VCOs) may still be slewing in phase, the IF itself may already be settled because the Source and LO are tracking. The two main VCOs are able to track the offset VCO settling because of their higher bandwidths. Therefore, measurements can be made sooner in the common offset mode and overall system speed is thus faster. However, the common offset mode can only be used when the source and LO frequencies are relatively close, because the range of the DDS limits the allowable difference. Additionally, the source and LO must be operating in the same frequency band. High-IF frequency measurements, such as Wide-Band Noise Figure, must operate in the independent offset mode. However, common offset mode is beneficial for typical S-parameter measurements where speed is an important parameter.
Harmonic Generator Mode

In most measurements, the presence of harmonics on the RF is undesirable. However, for measurements of phase in the harmonic measurements application, a reference is needed. The second and third harmonics of the source are used, and therefore must be of a significant enough level to be measured accurately. A harmonic generator diode can be switched into the circuit to pump the harmonics to levels above 45 dBc. Without the harmonic generator, the harmonics may be lower than 45 dBc.

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RECEIVER MODULE

THEORY OF OPERATION

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RECEIVER MODULE

The Receiver module is made up of the RF components that are used to configure the system for the various options. This encompases the frequency translation module, which produces the 125 kHz Intermediate Frequency, the Test and Reference channel Intermediate Frequency paths, the system 10 MHz time base, and the circuitry for the control of the RF components. At the end of the Intermediate Frequency paths, the signal to be measured is sampled and sent to the Central Processor Module. This module has Digital Signal Processing (DSP) prior to processing the numerical values into the CPU. Determination of magnitude and phase for S-Parameter measurements is done by calculating a single frequency Digital Fourier Transfer (DFT) of a coherently sampled Intermediate Frequency Signal. A Programmable Logic Device (PLD) accomplishes control of the receiver board and Analogue to Digital (ADC) clock generation. An intermediate frequency signal of 125 kHz was chosen because of the division ratio to the 10 MHz reference combined with the optimized sample rates used in the analogue to digital conversions.

Down Conversion Module

The Down Conversion Module (DCM) translates the Test Port and the Reference Port signals down to the 125 kHz intermediate frequency signal. The input at J5 takes the local oscillator signal from the Source Module. The signal is split into two paths, one for the Test Port Mixer and the other for the Reference Port Mixer. Two identical paths are used to provide the mixer local oscillator drive. The reason for the two paths is to maintain good isolation between the two signal paths. After the power divider, the local oscillator signal passes through a limiter that is used to flatten the power level variations of the incoming local oscillator signal. In so doing, it minimizes the AM to PM conversion in the local oscillator path. The local oscillator signal is filtered to provide a clean signal for the mixer. Built into the Down Conversion Module is a local oscillator doubler (used in 6 GHz models) or a tripler (used in 9 GHz models). The Test Port signal and the Reference Port signal go to J4 and J1, respectively. The outputs from the mixers are fed through buffer amplifiers before going to the intermediate frequency amplifiers.

Digital Interface

The Programmable Logic Device provides the main digital interface with the microprocessor. The load pulse, board select 5, data bits D0-D11, and address bits A0-A4 are inputs to this device that provide the add