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Digitization Of Rise And Fall Time

IP.com Disclosure Number: IPCOM000097303D
Original Publication Date: 1962-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Georgallis, GC: AUTHOR

Abstract

This is a circuit for digitizing either the rise or fall time of a pulse by converting either the rise or fall portion of the pulse into a triangular waveform. The latter has a width representative of the rise or fall time. The triangular pulse is used to condition a coincidence gate. This gates clock pulses to a counter to digitize the rise or fall time.

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Digitization Of Rise And Fall Time

This is a circuit for digitizing either the rise or fall time of a pulse by converting either the rise or fall portion of the pulse into a triangular waveform. The latter has a width representative of the rise or fall time. The triangular pulse is used to condition a coincidence gate. This gates clock pulses to a counter to digitize the rise or fall time.

The input pulse A having rise time T and amplitude V is fed into a phase inverter which produces output pulses A and A. Pulses A and A bar are two inputs of a three input positive And in coincidence with a timing gate pulse, the third input to the And. The positive And output follows the most negative input and is a triangular waveform having an amplitude V/2 and a width T. The 10% up point on the positive slope and the 10% up point on the negative slope of the triangular waveform correspond in time to the 10% up point and the 90% up point of the rise portion of input pulse A.

The And output is fed to the coincidence gate. Here, the 10% up point positive slope voltage and the 10% up point negative slope voltage of the triangular waveform are used as coincidence gate turn on and turn off voltages, respectively. Clock pulses are thus gated to the counter for a time proportional to the input pulse rise time. Knowledge of the number of clock pulses gated to the counter and the frequency of the clock pulses facilitates a determination of the rise time.

Resetting of the counter with...