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TM 11-6625-2779-14&P
TECHNICAL MANUAL
OPERATOR’ S, ORGANIZATIONAL, DIRECT SUPPORT, AND
GENERAL SUPPORT MAINTENANCE MANUAL
(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LISTS)
FOR
METER, AUDIO LEVEL TA-885/U
(HEWLETT-PACKARD MODEL 3555B)
(NSN 6625-00-255-1083)
HEADQUARTERS, DEPARTMENT OF THE ARMY
11 MARCH 1980
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TM 11-6625-2779-14&P This manual contains copyrighted material reproduced by permission of Hewlett-Packard Company. All rights are reserved. TECHNICAL MANUAL HEADQUARTERS DEPARTMENT OF THE ARMY. No. 11-6625-2779-14&P WASHINGTON, DC, 11 March 1980 OPERATOR'S, ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS AND SPECIAL TOOLS LISTS) FOR METER, AUDIO LEVEL TA-885/U (HEWLETT-PACKARD MODEL 3555B) (NSN 6625-00-255-1083) REPORTING ERRORS AND RECOMMENDING IM
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SECTION III. OPERATING INSTRUCTIONS (Cont.). Para Page Crosstalk measurements................................................................................................... 3-53 3-10 Identifying noise characteristics......................................................................................... 3-57 3-10 Measurements in DBC ...................................................................................................... 3-64 3-11 Measurement procedures.........................
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Model 3555B Table of Contents LIST OF ILLUSTRATIONS Number Page Number Page 1-1. Model 3555B Transmission and Noise Measuring Set.................................. 1-1 4-7. Simplified Peak Detection................................ 4-7 2-1. Power Plugs ................................................. 2-1 5-1. Balanced BNC to 310 Plug .............................. 5-2 3-1. Front Panel Controls, Indicators, 5-2. Level Accuracy Check ..................................... 5-2 and Connectors .......
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SECTION 0 INTRODUCTION 0-1. Scope This manual contains instructions for the operation, organizational maintenance and general support maintenance of Audio Level Meter TA-885/U. Throughout this manual, the equipment is referred to by its commercial designation of Hewlett-Packard Model 3555B Transmission and Noise Measuring Set or simply as the 3555B. Appendix A of the manual contains a list of references and appendix B contains the maintenance allocation chart (MAC). NOTE No direct support main
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b. Report of Packaging and Handling Deficiencies. Fill out and forward DD Form 6 (Packaging Improvement Report) as prescribed in AR 700-58/NAVSUPINST 4030.29/AFR 71-13/MCO P4030.29A, and DLAR 4145.8. c. Discrepancy in Shipment Report (DISREP) (SF 361). Fill out and forward Discrepancy in Shipment Report (DISREP) (SF 361) as prescribed in AR 55-38/NAVSUPINST 4610.33B/AFR 75-18 MCO P4610.19C and DLAR 4500.15. 0-4. Administrative Storage Before placing the TA-885/U in temporary storage (90 days),
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0-7. Items Comprising an Operable Equipment Audio Level Meter TA-885/U includes the meter, with cover and a power cord. The power cord is stored inside the cover of the set. 0-3
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Section I Model 3555B Table 1-1. Specifications VOICE FREQUENCY LEVEL MEASUREMENTS (20Hz balanced and 75 ohms unbalanced. to 20kHz) Return loss: TERM ONLY 600 ohms: 26dB min 3kHz to 150kHz Range: -91dBm to +31dBm 135 ohms: 26dB min to 600kHz 75 ohms: 30dB min to 3MHz Level accuracy: 20Hz to 20kHz: +0.5dB Bridging loss: less than 0.05dB at 10kHz 40Hz to 15kHz: +-0.2dB Balance: (Levels greater than -60dBm) greater than 70dB to 10kHz Note: For levels greater than +1 dBm, level accuracy greater tha
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Model 3555B Section I SECTION I GENERAL INFORMATION provided, balanced or unbalanced, bridged or 1-1. INTRODUCTION. terminated. For noise measurements a noise-to-ground (Ng) function is provided which provides 40dB of 1-2. The Hewlett-Packard Model 3555 B Transmission and Noise Measuring Set is a versatile set attenuation for longitudinal noise. For carrier frequencies 600 ohm, 135 ohm and 75 ohm impedances designed for uses in testing telecommunications equipment. The extreme sensitivity of
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Section I Model 3555B 1-5. A noise-to-ground (Ng) function is included Table 1-2. Accessory Equipment Supplied which permits the measurement of longitudinal noise. When making noise-to ground measurements the -hp- Part No. Description Quantity impedance between INPUT terminals is greater than 80 8120-1348 Power Cord 1 kilohms and is 100 kilohms between each terminal and 1470-0026 Battery, 45 Volt dry cell 1 ground. A HOLD function permits holding the line while 03555-26510 Test Board 1 noise m
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Model 3555B Section II SECTION II INSTALLATION 2-1. INSPECTION. Table 2-1. Suitable Batteries Meeting NEDA 202 Specifications 2-2. The set was carefully inspected both Manufacturer Mfr. Part No. mechanically and electrically before shipment. It should Hewlett-Packard 1420-0026 be physically free of mars or scratches and in perfect Western Electric KS-14370 electrical condition on receipt. To confirm this, the set Military BA-59 should be inspected for physical damage in transit, for Eveready
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Section II Model 355B 2-12. INSTALLATION AND REMOVAL OF POSITION TO PRESERVE BATTERY BATTERY. LIFE. IF THIS IS NOT BINDING, THE COVER FITS EASILY INTO PLACE. 2-13. To install or replace a battery, turn the four 1/4 turn fasteners on the battery cover on the rear of the 2-17. REPACKAGING FOR SHIPMENT. case counterclockwise to remove the cover. Lift off the cover, lift the battery out of its recess and unplug the 2-18. The following is a general guide for repackaging three-prong connector. at in
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Section III Model 3555B SECTION III OPERATING INSTRUCTIONS 3-1. INTRODUCTION. arranged for -48V or -24V ±2V with the negative terminal of the battery connected to 3-2. The Model 3555B Transmission and Noise the tip and the ground terminal connected to Measuring Set is an extremely versatile transmission and the sleeve. Current consumption by the noise measuring set which satisfies many of the 3555B is approximately 15mA. requirements in testing telecommunications equipment. The 3555B features a
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Section III Model 3555B Figure 3-1. Front Panel Controls, Indicators, and Connectors 3-2
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Model 3555B Section III Table 3-1. Front, Side and Rear Pane (1) S and G Jacks: Binding posts accepting banana Controls, Indicators and Connectors either the plugs, spade lugs, phone tips or bare wires for NOISE BRDG or the NOISE TERM before the connection to the case ground (G) and sleeves (S) NOISE WTG filters can be selected. of all INPUT jacks (12) and DIAL/AC MON jacks (9) FUNCTION Switch: A series of interlocking (10) and (11). pushbutton switches (with the exception of the (2) Shorting
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Section III Model 3555B Figure 3-2. Side Panel Controls and Connectors 3-4
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Model 3555B Section III Table 3-1. Front, Side and Rear Panel Controls, Indicators and Connectors (Cont’ d) 2. 135: Selects the input circuitry for 135 providing connection to the input circuitry of the ohm balanced circuits. A high measuring set. When the DIAL BAT pushbutton is frequency transformer is selected for depressed, the INPUT jacks are connected in this function. parallel with the DIAL/AC MON jacks. (13) Battery Cover: Removeable by four 1/4 turn screw 3. 75: Selects the input cir
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Section III Model 3555B frequency Transmission Measuring Set (TMS) for voice, lineman's hand set which was used for the dialing program and carrier multiplex measurements. The set will operation can be used for monitering by leaving it operate over a wide range of environmental conditions and connected to the clip posts. The jacks marked 310 will maintain a high degree of accuracy. accept a head phone or recorder connected to the tip and 3-16. In general, transmission level measurements are ri
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Model 3555B Section III when no input signal is present and a mechanical zero indicated on the recorder will be the algebraic sum of the adjust is not required. The actual input level to the set is RANGE. the algebraic sum of the black dBm meter scale and black 3-28. NOISE MEASUREMENT. RANGE setting. For example, RANGE is set to 40dBm 3-29. One of the primary functions of this set is to and the meter indicates -6.3dBm. The input level is then (- measure message circuit noise, both metallic an
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Section III Model 3555B 3-35. As an aid in identifying the source of noise, the 3-40. Crosstalk measurements involve low level DIAL/AC MON jacks can be used with a monitoring measurements and part of the meter indication may be 3- receiver to listen to the noise which will have 8 Model 3555B caused by noise in addition to crosstalk. approximately the same quality as that heard by a The general technique is to measure with crosstalk and subscriber. Particular types of noise like power line nois
