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Title & Document Type: 4935A Operating & Service
Manual
Manual Part Number: 04935-90029
Revision Date: November 1966
HP References in this Manual
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businesses are now part of Agilent Technologies. We have made no changes to this
manual copy. The HP XXXX referred to in this document is now the Agilent XXXX.
For example, model number HP8648A is now model number Agilent 8648A.
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Operating and Service Manual
HP 4935A
Transmission Impairment
Measuring Set
Serial Numbers
This manual applies to instruments with serial numbers prefixed:
:2846A
Copyright Hewlett-Packard Co./Colorado Telecommunications Division 1987
5070 Centennial Blvd., P.O. Box 7050, Colorado Springs, Colorado 80933
ALL RIGHTS RESERVED
Manual Part No: 04935-90029 Printed Nov. 1966
Microfiche Part No: 0493598804 Printed in U.S.A.
Warnirlgs/(:autions Model 4YXA
[ WARNING 1
SAFETY GROUNDING
If this instrument is to be energized via an autotransformer
Any interruption of the protective (grounding) conductor
for voltage reduction, make sure the common terminal is
(inside or outside the instrument) or disconnecting the
connected to the earthed pole of the power source.
protective earth terminal can make this instrument
dangerous. Intentional interruption is prohibited.
BEFORE SWITCHING ON THIS INSTRUMENT, the
protective earth terrninals of this instrument must be
connected to the protective conductor of the (mains)
HIGH VOLTAGE
power cord. The rnains plug shall only be inserted in a
socket outlet provided with a protective earth contact. The
p r o t e c t i v e actlon m u s t n o t b e n e g a t e d b y u s e o f a n Any adjustment, maintenance, and repair of the opened
extension cord (power cable) without a protective con- instrument under voltage should be avoided as much as
ductor (grounding). possible and, when inevitable, should be carried out only by
a skilled person who is aware of the hazard involved.
Make sure that only fuses with the required rated current
and of the specified type (normal blow, time delay, etc.) Capacitors inside the instrument may still be charged even
are used for replacement. The use of repaired fuses and the if the instrument has been disconnected from its source of
short-circuiting of fuse holders must be avoided. SUPPlY.
Whenever It is likely that the protection offered by fuses Adjustments and service described herein are performed
has been impaired, the instrument must be made with power supplied to the instrument while protective
inoperative and be secured against any unintended covers are removed. Energy available at many points, if
operation. contacted, result in personal injury.
LINE VOLTAGE BEFORE SWITCHING ON THIS INSTRUMENT, ensure
that the line power (mains) plug is connected to a
BEFORE SWITCHING ON THIS INSTRUMENT, make three-conductor line power outlet that has a protective
sure instrument requirements match the voltage of the ( e a r t h ) g r o u n d . ( G r o u n d i n g o n e c o n d u c t o r o f a two-
power source. conductor outlet is not sufficient.)
GROUNDING
BEFORE SWITCHING ON THIS INSTRUMENT, ensure
that all devices connected to this instrument are connected
to the protective (earth) ground.
ii
Model &%A IEC Symbols
IEC SYMBOLS
The follownq IS rl 1151 of key I EC symbols used by Hewlett-Packard. All symbols HZ Hertz (IEC 1174. symbol No. 365).
are normally applwd adlacent to the device requur~ng the symbol. They shall not
be placed on removable parts likely to be detached or lost. Contactor, normally closed. In order to avold confusion with
t h e s y m b o l f o r a capacitor. t h e deance b e t w e e n t h e
horizontal (as drawn here) lines should be at least equal to
lnstrucf~on Manual symbol: If necessary. to preserve the z the length of those lines (IEC 117-3, symbol No. 215.21.
!
A apparatus from damage !t IS necessary for the user to refer to
the mstruct~on manual, then shall the apparatus be marked
wth thlssymbol (IEC 348;16a).
In addltlon the following describes the use of Warmngs.
in HP Automatic Test System Manuals.
Cautions and Notes used
Warnings, cautions and notes. (All) Warmngs and caut!ons shall precede the text
Termnal dewces fad from the ~ntertor by live voltages that
to which each apples but notes may precede or follow applicable text depending
may be dangerous when connecting to or dlsconnectlng from
1 those dewces shall be marked wth the flash shown when the
volrdge exceeds 1 KV: The flash shall be red (IEC 348;lEc).
on the material to be highllghted. Warnings, cautions, and notes shall not contan
procedural steps nor shall they be numbered. When a warmng, caution, or note
consists of two or more paragraphs, the heading WARNING, CAUTION, NOTE,
shall not be repeated above each paragraph. If it is ever necessary to precede a
Earth Termunals. If the use of this symbol for the protectwe
-
- earth termmal 1s not permttted by National Standards, it may
be modlfled. for example, by bang placed irwde a circle (IEC
348.18a).
paragraph by both a warmng and a note, or a caution and a note, etc. they shall
appear m the sequence as noted, namely. warnings. cautions, notes. Such inserts
I" the text shall be short and concise and be used to emphasize important and
critical mstructtons.
AC current (IEC 117-l. symbol No. 3).
--- DC current fIEC 117-l. symbol No. 2).
AC or DC current (I EC 1 17-l. symbol No. 8).
An operating procedure, practtce. etc. which. If not
correctly followed, could result III personal injury or
loss of life.
Frame or chaws connection. The hatchmg may be com-
pletely or partly omitted if there II no ambiguity. If the
hatching is omated, the line representing the frame or chassis
shall be thrcker (I EC 117.1, symbol No. 87).
A Ampere (IEC 1174, symbol No. 356).
An operating procedure, practw, etc. which, if not
V Volt lltC 1174. symbol No. 357). strictly observed, could result tn damage to, or
destruction of, eqwpment.
VA Voltampere (I EC 1174, symbol No. 358).
NOTE: An operating procedure, condmon, etc. whwzh
w Watt (I EC 1174, symbol No. 3601. it is essential to hIghlIght.
Wh Watthour (I EC 1174, symbol No. 361). -health hazards precaution data. (All) When hazardous chemicals or adverse health
factors, in the environment or use of the equipment cannot be eliminated,
VAh Voltamperehour (IEC 1174, symbol No. 362). ,tppropriate precautionary requirements shall be mcluded.
iii/(iv blank)
Model 4935A Table of Contents
TABLE OF C:ONTENTS
Section Title Page Section Title Page
I. GENERAL INFORMATION 3-48. Signal Frequency Interference .................... .3-24
3-52. Impulse Noise.. .............................................. .3-24
l-l. Introduction.. ................................................... l - l 3-55. Noise-to-Ground Measurement.. ................ .3-25
l-3. General Description.. ..................................... l - l 3-59. Peak-to-Average Ratio Measurement.........3-2 5
l-5. Instrument Identification.. ............................. l-1
l-7. Specifications.. ................................................. l - l IV. PERFORMANCE TESTS
l-9. Safety Considerations.. .................................. .1-4
1-12. Related Manuals.. ........................................... l-4 4-l. Introduction ................................................... .4-l
1-14. User Repair.. ................................................... l-4 4-3. Equipment Required.. .................................. .4-l
1-16. Options and Accessories.. .............................. l-4 4-5. Test Record ................................................... .4-l
1-19. Warranty.. ...................................................... ..l- 4 4-7. Self Check ...................................................... .4-l
1-21. Recommended Test Equipment.. ................. l-4 4-9. Performance Verification.. ........................... .4-l
l-23. Battery Operation (0pt.s 001 & 003) .......... l-6 4-12. Performance Tests.. ...................................... .4-2
l-26. Charging the Batteries.. ........................... l-6 4-13. Transmitter Flatness at + 10dBm.. ........ .4-2
l-29. Operating Temperature.. ......................... l-6 4-14. Transmitter Flatness a t -40dBm.. ...........4-4
4-15. Receiver Accuracy at t 1ldBm
II. INSTALLATION & -4OdBm.. .............................................. .4-8
4-16. Autorange Test.. ...................................... .4-10
2-l. Introduction.. .................................................. .2-l 4-17. Filter Tests.. ............................................. .4-11
2-3. Initial Inspection.. .......................................... .2-l 4-18. Impulse Noise DAC Test.. ..................... .4-14
2-6. Preparation for Use.. ..................................... .2-l 4-19. Count Limit Test.. ................................... .4-16
2-7. Power Requirements.. ................................... .2-l 4-20. Termination Impedance Test.. .............. .4-17
2-9. Line Voltage Selection.. ................................. 2-l 4-21. Hold Tone Dropout Detector Test........4-19
2-11. Power Cable.. ................................................. .2-2 4-22. Hold Circuit Test .................................... .4-20
2-13. Operating Environment.. .............................. .2-2 4-23. Distortion T e s t ........................................ .4-21
2-16. Storage a n d Shipment.. ................................. .2-2 4-24. P/AR Test.. .............................................. .4-25
2-17. Environment.. ........................................... .2-2 4-25. Noise-to-Ground(Std. dc Opt. 001)....... .4-26
2-19. Instrument Packaging ................................... .2-2
V. ADJUSTMENTS/CALIBRATIONS
III. OPERATION
5-l. Introduction ................................................... .5-l
3-l. Introduction .................................................... .3-l 5-3. Safety Considerations.. ................................. .5-l
3-3. Self Check ....................................................... .3-l 5-5. Equipment Required.. .................................. .5-l
3-5. Error Messages.. ............................................ .3-l 5-6. Instrument Access.. ................................. .5-l
3-7. Operating Instructions .................................. .3-6 5-9. Adjustment Locations.. ................................. .5-l
3-9. Measurements ................................................ .3-7 5-11. Adjustments.. ................................................. .5-2
3-10. Measurement Principles ............................... .3-17 5-13. t 5V, + 14V, and -14V Power
3-12. Input-Output Switching ................................ .3-17 Supply Adjustments ...................................... .5-3
3-19. Level and Frequency Measurements.. ........ .3-18 5-14. Output Level & Transmit
3-21. 1000 H z Loss.. ................................................ .3-18 Monitor Loop Adjustments.. ................. .5-4
3-24. Frequency Shift .............................................. .3-18 5-15. Receiver Adjustments.. ................................. .5-5
3-26. Attenuation Distortion.. ................................ .3-18 5-17. Notch Filter Adjustments.. ........................... .5-7
3-30. SF Skip ............................................................ .3-19 5-18. Al3 P/AR Filter and Latch
3-32. Message Circuit Noise Measurements.. .... ..3-19 Adjustments(0pt.s 001 & 003). ................... .5-8
3.40. Noise Measurements ..................................... .3-22 5-19. Hold Circuit Adjustments.. .................... .5-9
3-42. Noise-with-Tone (Notched Noise) .............. .3-22
3-45. Signal-to Noise Measurement.. .................... .3-22
V
Table of Contents Model 4935A
TABLE OF CONTENTS (cord)
Section Title Page Section Title Page
VI. REPLACEABLE PARTS 8-80. Input Select/Notch Filter/
25 dB Amp.. ............................................. .8-17
6-l. Introduction.. .................................................. .6-l 8-85. Noise Filter Circuitry.. ............................ .8-17
6-3. Replaceable Parts List.. ............................... ..6- 1 8-97. Level Detectors ....................................... .8-19
6-5. Ordering Information ................................... .6-l 8-100. Impulse Noise Detectors.. ...................... .8-19
8-102. Transmitter .................................................... .8-19
VII. MANUAL CHANGES 8-104. T e s t Signal Generation Method.. .......... .8-20
811.3. Circuit Description.. ................................ .8-21
7-1. Introduction .................................................... .7-l 8-126. Power Supply Theory.. .................................. .8-23
7-3. Manual Changes.. .......................................... .7-l 8-128. A C Line Supplies .................................... .8-23
7-6. Manual Change Instructions......................... 7-l
. 8-131. Regulators.. .............................................. .8-24
8-139. Charger Board Theory of Operation.. ........ .8-25
VIII. SERVICE 8-141. Battery Charging.. ................................... .8-26
8-144. Power Source Selection.. ........................ .8-26
8-l. General Information .................................... ..8- 1 8-146. Relay Drive Circuitry.. ............................ .8-26
8-8. How Measurements are Made .................... .8-3 8-148. Inhibit Circuit ........................................... 8-26
8-10. Level a n d Frequency.. ............................. .8-4 8-153. Maintenance .................................................. .8-28
8-13. Noise.. ......................................................... 8-4 8-1.55. Periodic Maintenance.. ........................... .8-28
8-16. Noise-with-Tone ...................................... .8-4 8- 157. Failure Maintenance.. ............................. .8-28
8-19. Signal-to-Noise.. ....................................... .8-5 8-159. Component Replacement ...................... .8-28
8-22. Impulse Noise .......................................... .8-5 8-164. Soldering .................................................. .8-28
8-26. Noise-to-Ground (Std & Opt. 001). ...... .8-6 8-166 . Cleaning.. .................................................. .8-28
8-29. Peak-to-Average Ratio: P/AR 8-168. Disassembly .................................................... 8-29
(0pt.s 002 & 003) .................................... .a-6 8-169. Remove Case.. ......................................... .8-29
8-32. Frequency Measurement.. ............................ .8-6 8-171. Receiver Board/Shield Plate/
8-34. Level Measurement.. ..................................... .8-7 Battery Charger Board Disassembly.. ........ .8-29
8-38. How to Compute Frequency and Level 8-173. Switchboard/Front Panel Removal.. .......... .8-30
Measurement ................................................. .8-8 8-175. Transmitter Board Removal.. ...................... .8-30
8-39. Level Calculation Example.. ................... .8-8 8-177. Reassembly.. .................................................. .8-31
8-42. Control Theory of Operation.. ..................... .8-11 8-179. Power Supply Troubleshooting.. ................. .8-33
8-44. Microprocessor t o Instrument.. ................... .8-11 8-181. Minimum Core Troubleshooting.. .............. .8-34
8-45. System Latches.. ....................................... .8-H 8-183. Procedure .................................................. 8-35
8-48. Instrument t o Microprocessor.. ................... .8-12 8-186. Display Troubleshooting.. ...................... .8-36
8-51. Operator to Microprocessor ........................ .8-12 8-189. Control Troubleshooting.............................. .8-36
8-52. Keyboard Interrupt.. ................................ .8-12 8-190. Troubleshoot Keyscan/
8-54. Receiver Impedance Switches.. .............. .8-12 Interrupt Circuitry.. ................................. .8-36
8-57. Microprocessor t o Operator.. ...................... .8-13 8-192. Control and Counting Section
8-58. Displays.. ................................................... .8-13 Troubleshooting.. .......................................... .8-36
8-60. Instrument t o Operator ................................ .8-13 8-194. Transmitter Troubleshooting ...................... .8-37
8-62. Monitor Amp ........................................... .8-13 8-196. Transmit Clock Generator.. ................... .8-37
8-64. Beep Generator ....................................... .8-13 8-200. Transmitter Signature Analysis
8-66. Operator t o Instrument ................................ .8-13 Procedure.. ............................................... .8-37
8-68. Miscellaneous Circuitry.. .............................. .8-13 8-202. Digital-to-Analog Conversion ............... .8-39
8-73. Receiver Theory of Operation.. ................... .8-15 8-204. Filter and Signal Select Circuitry.. ........ .8-40
8-76. I/O Switching/Hold Circuits/ 8-207. Output Amplifier.. ................................... .8-42
Termination .............................................. .a-16 8-210. Transmit Monitor.. .................................. .8-43
8-212. Receiver Troubleshooting.. .......................... .8-43
vi
Model 4935A Table of Contents
TABLE OF CONTENTS
Section Title Page Section Title Page
8-217. Setup.. ........................................................ .8-44 8-259. Relay Drive Circuitry,
8-219. Overall Transmit Monitor T e s t ............. .8-44 Low Voltage Inhibit Circuitry.. ............. .8-53
8-222. Transmit Monitor Signal ........................ .8-45 8-261. Inhibit Circuitry AC and
8-225. Noise Filter.. ............................................. .8-45 Low Voltage.. ........................................... .8-54
8-227. Simplified Autorange Check.. ................ .8-46 8-263. Delay and Relay Drive Circuitry.. ......... .8-54
8-229. Detector Select.. ....................................... .8-47 8-265. AC and Low Voltage Inhibit
8-232. Inputs from Front Panel/ Troubleshooting ...................................... .8-55
Notch Filter/ 25dB Amp/Tone 8-267. Service Aids ................................................... .8-57
Dropout Signal Path.. .............................. .8-47 8-268. Service Selection of Input/
8-233. Setup.. ........................................................ .8-48 Notch Filter/25dB Amp.. ............................. .8-57
8-235. Input Transformer.. ................................. .8-48 8-270. Procedure.. ............................................... .8-57
8-237. Noise-to-Ground Input Path 8-272. Service Selection of Noise Filters
(Noise-to-Ground Units only) ............... .8-48 b y Hand.. ........................................................ .8-58
8-239. Tone Dropout Signal Path.. .................... .8-49 8-274. Procedure ................................................. .8-58
8-242. Notch Filter .............................................. .8-49 8-276. Service Selection of Autorange
8-246. Noise Filters ................................................... .8-49 Gain for Service.. ........................................... .8-58
8-248. Autorange ................................................. .8-49 8-278. Procedure ................................................. .8-58
8-250. Detector Troubleshooting.. .................... .8-50 8-279. Hand Selection of AX57 and A3C160
8-252. Impulse Noise Circuitry.. .............................. .8-50 (A3C57 and A3C160 for P/AR Units)
82.54. Charger Board Troubleshooting ................. .8-52 for Desired Frequency Response.. .............. .8-59
8-255. Procedure ................................................. .8-52 8-282. Hand Selection of C57 and Cl60.......... .8-60
8-257. Charge Circuitry/Charge 8-283. FiIters: Response of Each Stage.................. .8-60
Inhibit Circuitry ....................................... .8-52
vii
Table of Contents Model 4935A
LIST OF ILLUSTRATIONS
Section Title Page Section Title Page
l-l. Model 4935A Transmission Impairment 5-1. Output Level and Transmit Monitor
Measuring Set ................................................ .1-O Loop Adjustments.. ....................................... .5-4
l-2. Charge Acceptance at Various 5-2. Receiver Adjustments.. ................................. .5-5
Tempcraturcs.. ................................................ l-6 5-3. Hold Circuit Adjustments.. .......................... .5-9
2-l. Lint Voltage Selection.. ................................ .2-l 6-l. Exploded View Case and Covers.. .............. .6-4
6-2. Exploded View Assemblies and Cables.. .. ..6- 5
3-l. Front and Rear Panel Controls/ 6-3. Exploded View Battery Option.. ................. .6-7
Connectors/indicators.. ................................ .3-2
3 - 2 . Measurements ................................................ .3-6 7-l. A2 Switch Board Component Locator.. .... ..7-10
3-3. Input-Output Switching ................................. 3-17 7-2. A5 Charger Board Component Locator.. . ..7-14
3-4. Level and Frequency Mcasurcments.. ........ .3-18 7-3. Partial A5 Charger Board Schematic.. ....... .7-14
3-5. Message Circuit Noise Measurements ...... ..3-19 7-4. Al4 Transmitter Board Component
3-6. C-Mcssagc Weighting Characteristic.. ........ .3-20 Locator ........................................................... .7-15
3-7. 3 kHz Flat Weighting Characteristic.. ......... .3-20 7-5. Partial A4 and Al4 Schematic ...................... 7-16
3-8. Program Weighted liltcr.. ............................. .3-21 7-6. Al4 P/AR Transmitter Board
3-9. 15 kHz Flat Filter .......................................... .3-21 Component Locator.. .................................... .7-16
3-10. SOkBit Filter. ................................................... .3-22 7-7. A4 Transmitter Board Component
3-11. C-Message Weighting with Notch Locator ........................................................... .7-17
Characteristic.. ............................................... .3-23 7-8. Partial Power Supply Schematic.. ................ .7-18
3-12. Signal-to-Noise Measurement ..................... .3-23 7-9. Al3 P/AR Receiver Board Component
3-13. Impulse Noise Waveform Locator ........................................................... .7-19
Rcprcscntation.. ............................................. .3-24 7-10. A3 Receiver Board Component
3-14. Noise-to-Ground Related to Message Locator ........................................................... .7-20
Circuit Noise .................................................. .3-2.5 7-11. A3 Receiver Board Schematic
3-15. P/AR Transmit Signal Frcqucncy (Sheet 1 of 2) ................................................. .7-21
Spectrum.. ....................................................... .3-26 7-12. A3 Receiver Board Schematic
3-16. P/AR Transmit Signal Envelope.. ............... .3-26 (Sheet 2 of 2) ................................................. .7-23
7-13. Al3 P/AR Receiver Board Component
4-l. Transmitter Flatness Test Locator ........................................................... .7-25
a t + 10 dBm .................................................... .4-2 7-14. A3 Receiver Board Component
4-2. Transmitter Flatness Test Locator ........................................................... .7-26
a t -40 dBm ...................................................... .4-4 7-15. A3 Receiver Board Schematic
4-3. Reccivcr Test at + 11 dBm Diagram (Partial). ......................................... .7-27
a n d -40 dBm ................................................... .4-8 7-16. A4 Transmitter Board Component
4-4. Autorangc Test .............................................. .4-10 Locator ........................................................... .7-28
4-5. Filter Tests.. .................................................... .4-11 7-17. Al4 Transmitter Board Component
4-6. Impulse Noise DAC T e s t ............................. .4-14 Locator ........................................................... .7-28
4-7. Count Limit Test ........................................... .4-16 7-18. A4 Transmitter Board Schematic
4-8. Termination Impedance Test....................... .4-17 Diagram ......................................................... .7-29
4-9. Hold Tone Dropout Detector Test.. ........... .4-19 7-19. Al4 Transmitter Board Schematic
4-10. Hold (Xrcuit `Test.. ......................................... .4-20 Diagram (Partial). ......................................... .7-30
4-11. Distortion Test ................................................ 4-21 7-20. Al4 Transmitter Board Schematic
4-12. -40 dBm Distortion Test.. ............................. .4-22 Diagram (Partial). ......................................... .7-30
4-13. Filter Circuits ................................................. .4-23 7-21. A2 Switchboard Component Locator.. ....... .7-32
4-14. P/AR Test.. .................................................... .4-25 7-22. A2 Switchboard Schematic Diagram.. ........ .7-33
4-15. Noise-to-Ground Test.. ................................. .4-26 7-23. A3 Receiver Board Component
.. .
VW
Model 4935A Table of Contents
LIST OF ILLUSTRATIONS
Section Title Page Section Title Page
Locator.. .......................................................... .7-34 8-19. P/AR Signal Frequency Spectrum ............. .8-41
7-24. Al3 Receiver Board Component 8-20. P/AR Transmit Signal Envelope.. .............. .8-42
Locator.. .......................................................... .7-35 8-21. 20 H z Waveform ........................................... .8-43
7-25. Receiver Board Schematic 8-22. Transmit Monitor Test Output ................... .8-44
Diagram (Sheet 1 of 2) ................................. .7-36 8-23. 4935A Signal Flow Block Diagram.. ........... .8-67
7-26. Receiver Board Schematic 8-24. Al Front Panel Schematic Diagram.. .......... 8-69
Diagram (Sheet 2 of 2) ................................. .7-37 8-25. A2 Switchboard Component Locator.. ....... .8-70
7-27. A4 Transmitter Board Component 8-26. A2 Switchboard Schematic Diagram.. ........ .8-71
Locator.. .......................................................... .7-38 8-27. A3 Receiver Board Component
7-28. Al4 Transmitter Board Component Locator ........................................................... .8-72
Locator ............................................................ .7-39 8-28. Al3 Receiver Board Component
7-29. A4 Transmitter Board Schematic Locator ........................................................... .8-72
Diagram (Sheet 1 of 2) ................................. .7-40 8-29. A3 Receiver Board Schematic
7-30. A4 Transmitter Board Schematic Diagram (Sheet 1 of 4)................................. .8-73
Diagram (Sheet 2 of 2) ................................. .7-41 8-30. A3 Receiver Board Schematic
7-31. A5 Charger Board Component Locator......7-4 2 Diagram (Sheet 2 of 4). ................................ .8-75
7-32. A5 Charger Board Schematic Diagram.......7-4 3 8-31. A3 Receiver Board Schematic
Diagram (Sheet 3 of 4). ................................ .8-77
8-l. 4935A Main Block Diagram.. ....................... .8-l 8-32. A3 Receiver Board Schematic
8-2. Voltage-to-Frequency Conversion Diagram (Sheet 4 of 4). ................................ .8-79
Characteristics ................................................. 8-7 8-33. A4 Transmitter Board Component
8-3. Voltage-to-Frequency Conversion Locator ........................................................... .8-80
output ............................................................. .8-8 8-34. Al4 Transmitter Board Component
8-4. Frequency and Level Measurement Locator ........................................................... .8-80
Timing.. ........................................................... .8-9 8-35. A4 Transmitter Board Schematic
8-5. Control Circuitry Block Diagram.. .............. .8-11 Diagram (Sheet 1 of 5). ................................ .8-81
8-6. Receiver Block Diagram.. ............................. .8-14 8-36. A4 Transmitter Board Schematic
8-7. Switchboard Block Diagram ........................ .8-15 Diagram (Sheet 2 of 5). ................................ .8-83
8-8. Input-Output Switching ................................ .8-16 8-37. A4 Transmitter Board Schematic
8-9. Filter Block Diagram .................................... .8-17 Diagram (Sheet 3 of 5). ................................ .8-85
8-10. Autorange Block Diagram ........................... .8-18 8-38. A4 Transmitter Board Schematic
8-11. Stair-Step Sinewave.. ..................................... .8-20 Diagram (Sheet 4 of 5). ................................ .8-87
8-12. Transmitter Block Diagram ......................... .8-21 8-39. A4 Transmitter Board Schematic
8-13. Power Supply Block Diagram.. .................... .8-23 Diagram (Sheet 5 of 5)................................. .8-89
8-14. Charger Board Block Diagram.. .................. .8-25 8-40. A5 Charger Board Component Locator.. .. ,890
8-17. Instrument Troubleshooting ........................ .8-32 8-41. A5 Charger Board Schematic Diagram.. .. ..8-9 1
8-18. Stair-Step Sinewave.. ..................................... .8-39
ix
Table of Contents Model 4935A
LIST OF TABLES
Table Title Page Table Title Page
l - l . Specificalions.. ................................................. l-2 7-l. Manual Changes............................................ .7-l
l-2. Recommended T e s t Equipment.. ................. l-5
l-3. List of Parts Used for Performance 8-l. Measurements Summary.. ............................ .8-3
T e s t s ................................................................. l-5 8-2. Noise Amplification.. ..................................... 8-5
8-3. Reference Signatures.. .................................. .8-38
2-l. H P Plug Styles.. ............................................... 2-3 8-4. Wideband Filter Response ........................... S-40
8-5. 5 kHz Low Pass Filter Response ................ .8-40
4-1. Transmitter Flatness a t + 10 dBm ............... .4-3 8-6. Output Select MUX.. .................................... .8-41
4-2. Transmitter Flatness a t -40 dBm.. ............... .4-5 8-7. Transmit Monitor Test.. ............................... .8-43
4-3. Abbreviated Transmitter Flatness.. ............. .4-7 8-8. A3UlB Voltages ........................................... .8-51
4-4. Receiver A c c u r a c y T e s t Table ..................... .4-9 8-9. TP3 Voltages ................................................. .8-51
4-5. Abbreviated Receiver Accuracy S-10. Hand Selection of Noise Filters .................. .8-58
T e s t Table.. ..................................................... .4-9 8-11. Autorange States.. ......................................... .8-59
4-6. Autorange T e s t .............................................. .4-10 8-12. Hand Selection of C57 and Cl60................ .8-60
4-7. C-Message Filter Test.. ................................. .4-11 8-13. 4935A C-Message Filter.. ............................. .8-61
4-8. 3 kHz Filter Test.. .......................................... .4-12 8-14. 4935A 3 kHz Filter.. ...................................... .8-61
4-9. 15 khz flat Filter Test.. .................................. .4-12 8-15. 4935A 15 kHz Filter...................................... .8-61
4-10. Program Filter Test.. ..................................... .4-12 8-16. 4935A Program Filter.. ................................. .8-61
4-11. 50 kBit Filter Test.......................................... .4-13 8-17. 4935A 50 kBit Filter.. .................................... .8-62
4-12. Notch Filter Test.. .......................................... .4-13 8-18. 4935A N o t c h Filter.. ...................................... .8-62
4-13. Impulse Noise DAC Test ............................. .4-15 8-19. 4935A P/AR Filter ....................................... .8-62
4-14. Filter Circuit Parts List.. ............................... .4-23 8-20. 4935A 150 kHz Low Pass Filter .................. .8-62
4-15. Abbreviated Distortion Test ........................ .4-24 8-21. 4935A 110 kHz Low Pass Filter .................. .8-63
4-16. P/AR Filter R e s p o n s e s ................................ .4-25 8-22. Bell 41009 C-Message Filter.. ...................... .8-63
8-23. Bell 41009 3 kHz Filter................................. .8-64
6-l. Reference Designation and 8-24. Bell 41009 15 kHz Filter.. ............................. .8-64
Abbreviations ................................................. .6-2 8-25. Bell 41009 Program Filter.. .......................... .8-64
6-2. Manufacturer Code List ............................... .6-8 8-26. Bell 41009 50 kBit Filter.. ............................. .8-65
6-3. Replaceable Parts.. ........................................ .6-9 8-27. Bell 41009 P/AR Filter ................................ .8-65
8-28. Bell 41009 Notch Filter.. ............................... .8-65
x /(xi blank)
(hctral Inii,rmi,ti~,,,
Model 4935A
Figure f-1. Model 4935A f
ransnhdon Impairment Measuring set
Model 4935A
. t General Information
SECTION I
GENERAL INFORMATION
l-l. INTRODUCTION
1-2. This Operating and Service manual contains information to install, operate, maintain, and service
the HI' Model 49:{5A Transmission Impairment Measuring Set (TIMS). Figure 1-l shows the HP Model
49XA with cover and power cord. The manual is divided into eight major sections which provide the
following information:
SECTION I. GENERAL INFORMATION. Provides identification, specifications, related
manuals, and user-repair information.
SECTION II. INSTALLATION. Contains unpacking and inspection information, power
requirements, packaging, and storage instructions.
SECTION III. OPERATION. Includes an explanation of controls, connectors, indicators, and an
automatic self check procedure. Describes measurement principles and front panel instructions for
making each measurement.
SFCTION IV. PERFORMANCE TESTS. C' xtves test procedures required to verify that the
instrument's performance is in accordance with the specifications.
SECTION V. ADJUSTMENTS. Provides adjustment and calibration procedures.
SECTION VI. REPLACEARLE PARTS. Lists and identifies the instrument assemblies and
replaceable parts.
SEXTION VII. MANUAL CHANGES. Cor tams information to backdate the manual for
instruments with earlier serial numbers.
SECTION VIII. SERVICE. Includes theory of operation, troubleshooting procedures, flowcharts,
component locators, and schematic diagrams.
1-3. GENERAL DESCRIPTION
l-4. HI' Model 49XA is a Transmission Impairment Measuring Set (TIMS) which measures wideband
data and voice impairments. The frequency range over which measurements are made is 20 Hz to 110 kHz,
in steps of I, 10, 100, 1000, or 10,000 Hz. There are four permanently stored, fixed frequencies -404, 1004,
2804. and 271:s Hz. Any other four frequencies may be temporarily assigned and stored by the user.
1-5. INSTRUMENT IDENTIFICATION
l-6. A IO character serial number (OOOOAOOOOO) is inscribed on the rear panel. The first four digits and
the letter are the serial prefix. The serial prefix will change only if changes are made to the instrument; a
Manual Change Sheet will be included with the manuals of any instruments affected. Thelast five numbers
form the serial suffix which is unique to each instrument.
1-7. SPECIFICATIONS
l-8. Instrument specifications are listed in Table I -1.
l-l
Model 49:EA
Table l-l. Specifications
TRANSMITTER RECEIVER
Frequency Frequency
Frequency Range . . . . . . . . . .20 Hz to 110 kHz Frequency Range.. . . . . . . . . . . . .20 Hz to 110 kHz
Resolution Accuracy Resolution Accuracy
20-99,999 Hz 1 Hz f .005% of output frequency 20-9.999 Hz 1 Hz kO.5 Hz
100-l 10 kHz 10 Hz t .012% of output frequency 1 0 - 1 1 0 kHz 10 Hz +5 Hz
Store and Recall Functions
SK Skip . . . At power up skips a band from 2450-2750 HZ
Frequencies . . . . . At power up Fl is 404 HZ
F2 is 1004 Hz
F3 is 2804 Hz
F4 is 2713 Hz
Level Level
Range . . . . . . . . . . . . . . . .-40 to +13 dl3m Range . .._........................ -6Oto+13dBm
Resolution . . . . . . . . . . . . . . . . . . . . . 0.1 dB Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 dB
Flatness . . . . . . . . . . . . . . . . . _ . . . . . . . _(in dB) Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (in dl3)
FREQUENCY, Hz FREQUENCY (Hz)
20 200 15k 60k 85k 1 IOk 20 50 200 15k 60k 85k 1 IOk
z+13 z-+13
+im 5:
g;+1; Q---40
K.s
3 -40 3-60
Distortion: (in dB from fundamental)
(Includes harmonics, spurious and background noise within Receiver accuracy not specified below 500 Hz when using
a filter with a 3 dB bandwidth of 4 kHz or 4 f0, whichever 13562 termination.
is greater.)
At 1004 kHz accuracy is fO.l dB from -20 to +I3 dBm.
FREQUENCY (Hz)
_ 30 Hz 100 Hz 4k IlOk
Cross talk: >78 dB isolation @ 4 kHz, decreasing 6 dB per
octave above 4 kHz.
At 1004 Hz, 0 dBm, THD using a 4 kHz filter is more than
65 dB down from the fundamental.
Message Circuit Noise Message Circuit Noise
Transmitter is quiet terminated Range (@ 6OOa and 9OOn) . . . . . . . . . . .O to 100 dBrn
@ 13516 lower limit is 7 dB higher
Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 dB
Accuracy . . . . . . . . . . . . . . . .+ 1 dB from IO to 100 dBrn
+2 dB from 0 to IO dBrn
Filters . . . . . . . . . . . .C-Message, 3 kHz Flat, 15 kHz Flat,
Program, 50 kBit
Specifications describe the instrument's warranted performance. Supplemental characteristics shown in shaded areas or in
italics are intended to provide information useful in applying the instrument by giving typical, but non-warranted
performance parameters.
Model 4935A General Information
T a b l e l - l . SpecificatilJns (Continued)
1
TRANSMITTER RECEIVER
Noise with Tone Noise with Tone
Frequency . . . . . . . . . . . . . . 1004 Hz fixed tone Notch Filter. . . . . . >50 dB rejection from 995 to 1025 HZ
(For other specifications, see Level and Frequency) Range (@ 600R and 900R) . . . . . . . . . . . . . . I O - 1 0 0 dBrn
Accuracy . . . . . . . . . . . . . . . . . ?I dB from 20 to 100 dBrn
*2 dB from 10 to 20 dBrn
(For other specifications, refer to Message Circuit Noise)
Signal-to-Noise Ratio Signal-to-Noise Ratio
Frequency . . . . . . . . . . . . . . . . 1004 Hz fixed tone Signal Level Range . . . . . . . . . . . . . . . . . . .-40 to +I 3 dBm
(For other specifications, see Level and Frequency) Ratio Range . . . . . . . . . . . . . . . . . . . . . . . . . . . IO to 45 dB
Resolution ................................. .I dB
3-Level Impulse Noise 3-Level Impulse Noise
Frequency . . . . .1004 Hz fixed tone or quiet terminated Level Range . . . . . . . . . . . . . . . . . . . . . . . .-40 to +I3 dBm
depending on filter selection Notch Filter. . . . . . . . . . . . . . . . . . . . .See Noise with Tone
(For other specifications, see Level and Frequency) Threshold Ranges (@ 6OOfi)
Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 to 109 dBrn
Mid .4 dB above Low to a maximum of 109 dBrn
High : : : : .... .8 dB above Low to a maximum of 109 dBrn
Loss of Holding Tone Indication . . . . . . . . . . . . Minus sign
Threshold Accuracy (above 40 dBrnl . . . . . . . . . . . . + 1 dB
Count Timer . . . . . . . . . . . . . . . 5, 15,60 min. or non-stop
Count Range . . . . . . . . . . . . . . . O-9999 for each threshold
Count Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8per sec.
Noise-to-Ground Noise-to-Ground
Transmitter is quiet terminated Range (@ 600R and 9OOfi) . . . . . . . . . . . . .50 to 130 dBrn
Resolution.................................. 1 dB
Accuracy ................................ +I .5 dl3
P/AR (Optional) P/AR (Optional)
Frequency . . Signal spectrum is a complex pulse train of P/AR Range. . . . . . . . . . . . . . . . . . . .O to 120 P/AR units
16 frequencies between 140 Hz and 3890 Hz. Resolution ........................... 1 P/AR unit
Level Range . . . . . . . . . . . . . . . . . . . . .-40 to 0 dBm Accuracy (from 30 to 110 P/AR units) . . . +2 P/AR units
Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 dB Level Range . . . . . . . . . . . . . . . . . . . . . . . .-40 to +3 dBm
Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I dB
Temperature Range:
Operating . . . . . . . . . . . . . . 0