Browse Prior Art Database

Pulse Length Discriminator

IP.com Disclosure Number: IPCOM000073993D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Petit, PL: AUTHOR

Abstract

This pulse-length discriminator distinguishes between narrow and long pulse signals. As an example, it is assumed that the signals come from a telegraphic terminal and the narrow and the long pulses are 2O ms and 500 ms, respectively. The circuit and the voltages at various points A, B, C, D are shown. The short control pulse corresponds to the call signal, the long control pulse to the end signal.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 94% of the total text.

Page 1 of 2

Pulse Length Discriminator

This pulse-length discriminator distinguishes between narrow and long pulse signals. As an example, it is assumed that the signals come from a telegraphic terminal and the narrow and the long pulses are 2O ms and 500 ms, respectively. The circuit and the voltages at various points A, B, C, D are shown. The short control pulse corresponds to the call signal, the long control pulse to the end signal.

In the case of a long time inversion of the control signal CL.SlG., the voltage VA at point A remains at -48 V and CL is charged between +48 V and VA. After a time interval t, the voltage VB is back at 0.7 V. When the voltage VC returns to +48 V the voltage VB does not allow the firing of thyristor Th; the relay is not actuated and D remains at voltage -V. In the case of a short inversion of the control signal CL.SIG., the return of the control signal to +48 V causes the return of the voltage VA to 0 V and the increase of the voltage VC, which tends to +48 V with a time constant imposed by the relay. The increase of the voltage VA causes a quick increase of the voltage VB. The various time constants can be determined such as, during their evolution, the voltages at C and B reach relative values causing the thyristor Th to fire and consequently the relay to be actuated.

After a call the thyristor is ON, but when the line is seized for the message the control signal line is cutoff by a switch, not shown, that resets the relay. Then the transmis...