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Keysight 478A Operating and Service Manual

Notices

Copyright Notice

© Keysight Technologies 2008 - 2020
No part of this manual may be repro-

duced in any form or by any means 

(including electronic storage and 

retrieval or translation into a foreign 

language) without prior agreement and 

written consent from Keysight Technol-

ogies as governed by United States and 

international copyright laws.

Manual Part Number

00478-90021

Edition

Edition 3, January 23, 2020

Printed in:

Printed in Malaysia

Published by:

Keysight Technologies

Bayan Lepas Free Industrial Zone,

11900 Penang, Malaysia

Technology Licenses 

The hardware and/or software 

described in this document are fur-

nished under a license and may be 

used or copied only in accordance with 

the terms of such license.

Declaration of Conformity

Declarations of Conformity for this 

product and for other Keysight prod-

ucts may be downloaded from the 

Web. Go to 

http://www.keysight.com/

go/conformity

. You can then search by 

product number to find the latest Dec-

laration of Conformity.

U.S. Government Rights

The Software is “commercial computer 

software,” as defined by Federal Acqui-

sition Regulation (“FAR”) 2.101. Pursu-

ant to FAR 12.212 and 27.405-3 and 

Department of Defense FAR Supple-

ment (“DFARS”) 227.7202, the U.S. 

government acquires commercial com-

puter software under the same terms 

by which the software is customarily 

provided to the public. Accordingly, 

Keysight provides the Software to U.S. 

government customers under its stan-

dard commercial license, which is 

embodied in its End User License 

Agreement (EULA), a copy of which can 

be found at 

http://www.keysight.com/

find/sweula

. The license set forth in the 

EULA represents the exclusive authority 

by which the U.S. government may use, 

modify, distribute, or disclose the Soft-

ware. The EULA and the license set 

forth therein, does not require or per-

mit, among other things, that Keysight: 

(1) Furnish technical information 

related to commercial computer soft-

ware or commercial computer software 

documentation that is not customarily 

provided to the public; or (2) Relinquish 

to, or otherwise provide, the govern-

ment rights in excess of these rights 

customarily provided to the public to 

use, modify, reproduce, release, per-

form, display, or disclose commercial 

computer software or commercial com-

puter software documentation. No 

additional government requirements 

beyond those set forth in the EULA 

shall apply, except to the extent that 

those terms, rights, or licenses are 

explicitly required from all providers of 

commercial computer software pursu-

ant to the FAR and the DFARS and are 

set forth specifically in writing else-

where in the EULA. Keysight shall be 

under no obligation to update, revise or 

otherwise modify the Software. With 

respect to any technical data as 

defined by FAR 2.101, pursuant to FAR 

12.211 and 27.404.2 and DFARS 

227.7102, the U.S. government 

acquires no greater than Limited Rights 

as defined in FAR 27.401 or DFAR 

227.7103-5 (c), as applicable in any 

technical data.

Warranty

THE MATERIAL CONTAINED IN THIS 

DOCUMENT IS PROVIDED “AS IS,” 

AND IS SUBJECT TO BEING 

CHANGED, WITHOUT NOTICE, IN 

FUTURE EDITIONS. FURTHER, TO THE 

MAXIMUM EXTENT PERMITTED BY 

APPLICABLE LAW, KEYSIGHT DIS-

CLAIMS ALL WARRANTIES, EITHER 

EXPRESS OR IMPLIED, WITH REGARD 

TO THIS MANUAL AND ANY INFORMA-

TION CONTAINED HEREIN, INCLUD-

ING BUT NOT LIMITED TO THE 

IMPLIED WARRANTIES OF MER-

CHANTABILITY AND FITNESS FOR A 

PARTICULAR PURPOSE. KEYSIGHT 

SHALL NOT BE LIABLE FOR ERRORS 

OR FOR INCIDENTAL OR CONSE-

QUENTIAL DAMAGES IN CONNECTION 

WITH THE FURNISHING, USE, OR 

PERFORMANCE OF THIS DOCUMENT 

OR OF ANY INFORMATION CON-

TAINED HEREIN. SHOULD KEYSIGHT 

AND THE USER HAVE A SEPARATE 

WRITTEN AGREEMENT WITH WAR-

RANTY TERMS COVERING THE MATE-

RIAL IN THIS DOCUMENT THAT 

CONFLICT WITH THESE TERMS, THE 

WARRANTY TERMS IN THE SEPARATE 

AGREEMENT SHALL CONTROL.

Safety Information

CAUTION

A CAUTION notice denotes a hazard. It 

calls attention to an operating proce-

dure, practice, or the like that, if not 

correctly performed or adhered to, 

could result in damage to the product 

or loss of important data. Do not pro-

ceed beyond a CAUTION notice until 

the indicated conditions are fully 

understood and met.

WARNING

A WARNING notice denotes a hazard. It 

calls attention to an operating proce-

dure, practice, or the like that, if not 

correctly performed or adhered to, 

could result in personal injury or death. 

Do not proceed beyond a WARNING 

notice until the indicated conditions are 

fully understood and met.

Содержание 478A

Страница 1: ...Keysight 478A Thermistor Mount Operating and Service Manual...

Страница 2: ...rights customarily provided to the public to use modify reproduce release per form display or disclose commercial computer software or commercial com puter software documentation No additional governm...

Страница 3: ...vice facility designated by Keysight Technologies Buyer shall prepay shipping charges to Keysight Technologies and Keysight Technologies shall pay shipping charges duties and taxes for products return...

Страница 4: ...ign manufacture and intended use of the instrument Keysight Technologies assumes no liability for the customer s failure to comply with these requirements CAUTION This product is designed for use in I...

Страница 5: ...ring and Control Instrument product The affixed product label is as shown below Do not dispose in domestic household waste To return this unwanted instrument contact your nearest Keysight Service Cent...

Страница 6: ...6 Keysight 478A Operating and Service Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK...

Страница 7: ...ntroduction 15 Instruments Covered by Manual 15 Incoming Inspection 15 2 Operation Biasing Thermistors 18 Maximum Input 18 Average Power 18 Pulse Energy and Peak Power for 478A 432 Combination 19 Puls...

Страница 8: ...acteristics 4 Maintenance Mechanical Shock 34 Check on Thermistor Match 34 Repair 36 Thermistor Assembly Replacement Procedure 39 Removal Procedure 41 Installation Procedure 42 Recalibration 43 A Appe...

Страница 9: ...478A Thermistor Resistance Match 35 Figure 4 3 Thermistor Compensation 37 Figure 4 4 Model 478A Thermistor Mount Assembly 41 Figure 4 5 Keysight Model 478A Printed Circuit Assy Wiring 42 Figure A 1 Sc...

Страница 10: ...10 Keysight 478A Operating and Service Manual Figure A 8 Model 478A Thermistor Mount Assembly P O Change B 53 Figure A 9 Keysight Model 478A Printed Circuit Assembly Wiring P O Change B 54...

Страница 11: ...8A Operating and Service Manual 11 List of Tables Table 2 1 Methods of Switching Off RF Output of Various Keysight Signal Generators 22 Table 4 1 Replaceable Parts 39 Table A 1 Manual Changes by Seria...

Страница 12: ...12 Keysight 478A Operating and Service Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK...

Страница 13: ...Keysight 478A Thermistor Mount Operating and Service Manual 13 1 General Information Introduction 15...

Страница 14: ...1 General Information 14 Keysight 478A Operating and Service Manual Figure 1 1 Keysight Model 478A Thermistor Mount...

Страница 15: ...lished by mounting the leads of all four thermistors on a common thermal conductor to ensure a common thermal environment This conductor is thermally insulated from the main body of the mount so the t...

Страница 16: ...1 General Information 16 Keysight 478A Operating and Service Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK...

Страница 17: ...Keysight 478A Thermistor Mount Operating and Service Manual 17 2 Operation Biasing Thermistors 18...

Страница 18: ...e Power The 478A 431 and 478A 432 combinations can measure average power up to 10 mW To measure power in excess of 10 mW insert a calibrated directional coupler such as one of the Keysight Technologie...

Страница 19: ...watts For example a 40 mW 250 s pulse contains 10 W s of energy Pulses longer than 250 s are allowed to contain more energy but peak power must not exceed 200 W Figure 2 1 and Figure 2 2 interpret th...

Страница 20: ...1 and Figure 2 2 Square wave modulation is a special case of pulse modulation and maximum power meter reading versus square wave frequency is illustrated in Figure 2 3 This figure also holds for sine...

Страница 21: ...ipated in the thermistor mount PIN diode modulators of Keysight model 8741A 8716A modulators and 8614A 8616A signal generators however are not subject to this consideration because output filtering pr...

Страница 22: ...sight signal generators are listed in Table 2 1 After allowing time for the mount to stabilize thoroughly follow zero set procedures in the 431 or 432 power meter manual and then turn on the RF source...

Страница 23: ...e reading When the reading no longer drifts disconnect the mount from the source terminate the mount if necessary as described in Thermistor Mount Disconnected for Zero Set on page 23 and then the zer...

Страница 24: ...Disconnected for Zero Set on page 23 from the source For example if the impedance presented by the RF system to 10 kHz is low 1 k or less terminate the thermistor mount in a 50 resistor or a short On...

Страница 25: ...en it is inconvenient to turn the RF power off while using the 478A 432 combination simply remove the mount from the source and using the COARSE and FINE ZERO zero the 432 Figure 2 5 Schematic Diagram...

Страница 26: ...creates a DC voltage Thus two thermocouple voltages of opposite relative polarity are formed one at each junction to each thermistor element Ideally each thermocouple voltage would be equal in magnit...

Страница 27: ...Calculate and record substituted power as P1 5 Reverse connection polarity between the calibrator and power meter 6 Re zero and re null power meter if necessary 7 By DC substitution duplicate lower m...

Страница 28: ...s in temperature and thus minimize drift During 431 478A operation sufficient amounts of DC and 10 kHz bias currents are supplied from the 431 power meter to heat the thermistors until their resistanc...

Страница 29: ...ly the total amounts of heat applied to reduce their series resistance equally must be equal 432 Power Detection Under normal operation the total power applied to heat thermistor pair D see Figure 4 1...

Страница 30: ...2 Operation 30 Keysight 478A Operating and Service Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK...

Страница 31: ...t Operating and Service Manual 31 3 Specifications and Characteristics For the specifications and characteristics of the 478A Thermistor Mount refer to the datasheet at http literature cdn keysight co...

Страница 32: ...3 Specifications and Characteristics 32 Keysight 478A Operating and Service Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK...

Страница 33: ...Keysight 478A Thermistor Mount Operating and Service Manual 33 4 Maintenance Mechanical Shock 34...

Страница 34: ...e thermistor mount pins are shown in Figure 4 1 Note that the small battery in series with the Keysight model 3440 digital voltmeter is connected in opposition to the power supply The value of this bu...

Страница 35: ...nance 4 Keysight 478A Operating and Service Manual 35 Figure 4 2 Check on Model 478A Thermistor Resistance Match WARNING Under no conditions should the mount be required to carry a current higher than...

Страница 36: ...h is known to be good A faulty cable will not have continuity through the respective connector pins or may have poor contact in the mount connector Poor contact will show as an intermittancy or a grea...

Страница 37: ...ure between 1000 and 5000 An open or shorted reading indicates the need for replacement of the thermistors If the resistance reading is satisfactory it may be possible to recompensate the mount and re...

Страница 38: ...o with each adjusting screw 5 Replace cover and three screws A The instrument is now operative MOUNT RES 200 W MOWER ON CAUTION If there is a sudden jump in meter indication when advancing either scre...

Страница 39: ...placement Procedure The procedure consists of removing the damaged thermistor assembly the printed circuit assembly and replacing them with pretested assemblies included in Thermistor Assembly Replace...

Страница 40: ...nd should be 1 5 or less The following special tools may be required for the completion of this procedure One small screwdriver 0 070 tip suitable for removing a 00 90 x 1 8 screw One pair of tweezers...

Страница 41: ...ree wires between the printed circuit assembly and the receptacle connector from the printed circuit assembly 4 In early thermistor assemblies there is a 00 90 x 1 8 screw used to connect the RF Therm...

Страница 42: ...nect the three wires from receptacle connector to printed circuit assembly Figure 4 5 Keysight Model 478A Printed Circuit Assy Wiring 2 Install the three insulator bushings in the thermistor assembly...

Страница 43: ...5 The adjustment is made with the 5 16 23 setscrew which is secured by a locknut The setscrew should not be moved unless SWR is being calibrated Efficiency may be checked by comparing to a known good...

Страница 44: ...4 Maintenance 44 Keysight 478A Operating and Service Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK...

Страница 45: ...Keysight 478A Thermistor Mount Operating and Service Manual 45 A Appendix A Introduction 46 Manual Changes 47...

Страница 46: ...o Table A 1 Make all of the manual changes listed opposite your instrument s serial number The manual changes should be performed in the sequence shown in the table For example Change B should be done...

Страница 47: ...al Changes Change A Replace Figure 2 5 Schematic Diagram of a Model 478A Thermistor Mount when Connected to a 431 Power Meter on page 25 with Figure A 1 Figure A 1 Schematic Diagram of a Model 478A Th...

Страница 48: ...Manual Replace Figure 4 1 Schematic Diagram of a Model 478A Thermistor Mount when Connected to a 432 Power Meter on page 34 with Figure A 2 Figure A 2 Schematic Diagram of a Model 478A Thermistor Mou...

Страница 49: ...Keysight 478A Operating and Service Manual 49 Replace Figure 4 2 Check on Model 478A Thermistor Resistance Match on page 35 with Figure A 3 Figure A 3 Check on Model 478A Thermistor Resistance Match...

Страница 50: ...sight 478A Operating and Service Manual Change B Replace Figure 2 4 Source Impedance Shunting One RF Thermistor Mount on page 23 with Figure A 4 Figure A 4 Source Impedance Shunting One RF Thermistor...

Страница 51: ...nual 51 Replace Figure 2 5 Schematic Diagram of a Model 478A Thermistor Mount when Connected to a 431 Power Meter on page 25 with Figure A 5 Figure A 5 Schematic Diagram of a Model 478A Thermistor Mou...

Страница 52: ...Manual Replace Figure 4 1 Schematic Diagram of a Model 478A Thermistor Mount when Connected to a 432 Power Meter on page 34 with Figure A 6 Figure A 6 Schematic Diagram of a Model 478A Thermistor Mou...

Страница 53: ...eplace Figure 4 3 Thermistor Compensation on page 37 with Figure A 7 Figure A 7 Thermistor Compensation P O Change B Replace Figure 4 4 Model 478A Thermistor Mount Assembly on page 41 with Figure A 8...

Страница 54: ...4 Keysight 478A Operating and Service Manual Replace Figure 4 5 Keysight Model 478A Printed Circuit Assy Wiring on page 42 with Figure A 9 Figure A 9 Keysight Model 478A Printed Circuit Assembly Wirin...

Страница 55: ...is subject to change without notice Always refer to the Keysight website for the latest revision Keysight Technologies 2008 2020 Edition 3 January 23 2020 Printed in Malaysia 00478 90021 00478 90021...

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