Browse Prior Art Database

Portable TDR Coaxial Cable Tester

IP.com Disclosure Number: IPCOM000047213D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Whedon, WT: AUTHOR

Abstract

This tester eliminates the need for an oscilloscope and technical expertise in the interpretation of Time Domain Reflectometry (TDR) oscillograms and displays. A pulse generator 10 is used to put a signal on the coax (not shown) to be tested. This pulse is also fed to the signal processor 12 to start a timebase clock 13. Reception of the reflected pulse is effected by a high-speed differential amplifier 14, which fires a second pulse (stop pulse) to 12 and 13. The distance to the end of the cable (or defect) is read out directly in tens of feet on a digital display 16. This readout is a function of time of start to time of stop, and the timebase clock 13 may be so designed as to give one pulse/ten feet, or some other, as desired, e.g., metric readout.

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Portable TDR Coaxial Cable Tester

This tester eliminates the need for an oscilloscope and technical expertise in the interpretation of Time Domain Reflectometry (TDR) oscillograms and displays. A pulse generator 10 is used to put a signal on the coax (not shown) to be tested. This pulse is also fed to the signal processor 12 to start a timebase clock 13. Reception of the reflected pulse is effected by a high-speed differential amplifier 14, which fires a second pulse (stop pulse) to 12 and 13. The distance to the end of the cable (or defect) is read out directly in tens of feet on a digital display 16.

This readout is a function of time of start to time of stop, and the timebase clock 13 may be so designed as to give one pulse/ten feet, or some other, as desired, e.g., metric readout. The signal processor 12 consists of an ADC (analog-to-digital converter) and processing elements; PROM and supporting discrimination logic, PLA, hardwired ROM, etc., which are programmed to differentiate between as many levels and polarities of return pulses as needed to diagnose the state of the coax under test. In operation, power (internally or externally derived) is applied to the tester, counters and indicators are reset, and the coax to be tested is attached at 18 by appropriate adapters. The test button 20 is then depressed, and the cable condition will be indicated, along with its length, on the display panel.

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