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Diode Limiter Failure Detection Circuit

IP.com Disclosure Number: IPCOM000092768D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Garcia, JG: AUTHOR [+2]

Abstract

The circuit detects any failure of line diode limiters. In the drawing there are a transmission line, a line transformer Tr with the associated line limiter, a switch, a line feeder with an AC signal emitter, and a limiter failure detection circuit associated with the feeder.

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Diode Limiter Failure Detection Circuit

The circuit detects any failure of line diode limiters. In the drawing there are a transmission line, a line transformer Tr with the associated line limiter, a switch, a line feeder with an AC signal emitter, and a limiter failure detection circuit associated with the feeder.

In order to test a given limiter, the corresponding line is connected through the switch to the detection circuit and the emitter is activated. The latter applies through the switch a current high enough to obtain a voltage level of 6V peak on the transmission line.

If the limiter is operative, such a current is flowing through the limiter diodes. As there are three diodes in series the voltage on the transmission line is so limited to about 2V.

If the limiter is operative, such a current is flowing through the limiter diodes. As there are three diodes in series the voltage on the transmission line is so limited to about 2V.

On the contrary, when the limiter is open, the peak-to-peak swing on the transmission line is higher than 4V. Such a voltage is able to turn on the input transistor of the detection circuit, producing an output signal.

The diode assembly of the detection circuit acts as a limiter having two additional diodes on each side. Thus the conducting threshold is displaced by about 1 V.

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