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Bipolarity Voltage Level Discriminator

IP.com Disclosure Number: IPCOM000093337D
Original Publication Date: 1967-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Lowe, GHT: AUTHOR

Abstract

Conventional voltage level discriminators using tunnel diodes are unipolar. Usually a discriminator that detects a positive going pulse does not respond to a negative going pulse and vice versa.

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Bipolarity Voltage Level Discriminator

Conventional voltage level discriminators using tunnel diodes are unipolar. Usually a discriminator that detects a positive going pulse does not respond to a negative going pulse and vice versa.

This circuit uses a single tunnel diode TD and responds to both negative and positive going pulses. This is accomplished by a first tunnel rectifier circuit forward biased between the input terminal and the anode of TD. The latter is connected through a second reverse biased rectifier D6 to the circuit output. A third tunnel rectifier is connected in reverse bias between the input and the cathode of TD. Suitable biasing is employed to enable TD to operate like a monostable vibrator.

A positive-going input pulse reverse biases tunnel rectifiers D1 and D2 driving current into TD. Tunnel rectifiers D3 and D4 are forward biased and present a high impedance. When the input signal reaches a level where the signal current plus the DC bias current exceed the peak current of TD, the latter switches from its high current and low voltage state to its low current and high voltage state.

In the case of a negative-going pulse, D1 and D2 are forward biased and present a high impedance. D3 and D4 are reverse biased. The negative-going signal thus draws current through TD and tunnel rectifier D5 blocks any current flow from ground to input. This increase in current plus the DC bias of TD triggers TD when their sum exceeds the peak current. Tunnel rec...