Wi Ryong Hwan, a researcher at the Faculty of Communications, has developed a device for measuring fault points of cables by a time-digital converter.
Several methods such as TDR, FDR, TFDR, STDR, etc. are used to localize fault points of cables.
The most representative method is TDR. Here, a measurement device emits a pulse and detects the reflecting pulse. It determines a fault point in a cable by calculating time intervals between transmitted and reflected pulses.
With the appearance of a time-digital transformer in recent years, measurement accuracy has been improved significantly. The transformer measures time intervals according to the delay time of CMOS gate and converts time intervals of tens or hundreds of ps into digits.
To develop the device, he used microprocessor PIC16F877 and time-digital transformer GC7820A.
An error of about 0.2 % was achieved for a communication cable of 1 000m.
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