Browse Prior Art Database

Repetitive, Fast Rise Time Pulse Level Detector

IP.com Disclosure Number: IPCOM000092718D
Original Publication Date: 1967-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Jordan, PV: AUTHOR [+2]

Abstract

The circuit is a pulse level detector which provides a DC analog output equivalent of the maximum or minimum voltage level of a repetitive, fast rise-time pulse. Each of the two circuit sections has two matched transistors and an operational amplifier that is independent of drift due to the effect of temperature on the transistors.

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Repetitive, Fast Rise Time Pulse Level Detector

The circuit is a pulse level detector which provides a DC analog output equivalent of the maximum or minimum voltage level of a repetitive, fast rise-time pulse. Each of the two circuit sections has two matched transistors and an operational amplifier that is independent of drift due to the effect of temperature on the transistors.

With switch S1 in the position shown, the output is equal to the positive peak amplitude of the input signal. Incoming signals of an AC input are applied to the base of transistor T3 and charge up capacitor C1 in its emitter circuit. Such charge is to a value of the applied voltage minus the base-emitter voltage drop of the transistor. The charging rate, at the emitter of T3, can be controlled by appropriate selection of C1 and resistor R1 of the emitter circuit of T3.

When the input waveform falls below a maximum level, T3 becomes reverse biased. The charged C1 discharges through R1 of the emitter circuit, with a discharge time substantially greater than the charging time, with respect to the time between incoming input pulses. The voltage across C1, at T3, is connected as an input to operational amplifier A1.

There is a feedback loop composed of A1, transistor T4, and associated resistances. All these form a voltage translation circuit such that the voltage appearing at the emitter of T3 is increased by the base-emitter voltage of T4. Since A1, by T4, forces its two inputs to equalize,...