Browse Prior Art Database

Gray Level Multiplex Transmission

IP.com Disclosure Number: IPCOM000090956D
Original Publication Date: 1969-Aug-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Seitzer, D: AUTHOR

Abstract

Video scanners 1...N, scanning N pictures in parallel, are connected to a priority switch. This allows one scanner to be switched through to a common transmission channel, which recognizes the termination of a run-length within a certain gray-level amplitude aperture to which the scanner is set. Associated with scanners 1...N are sampling request detectors SRD consisting of differential amplifiers DA 1 and DA 2, a hold circuit and an aperture reference circuit. If in any one scanner the video signal reaches either one of the limits of the aperture, i.e., when it terminates a run-length, a threshold device TD is caused by differential amplifier DA 1 to send a Request signal to the priority switch.

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Gray Level Multiplex Transmission

Video scanners 1...N, scanning N pictures in parallel, are connected to a priority switch. This allows one scanner to be switched through to a common transmission channel, which recognizes the termination of a run-length within a certain gray-level amplitude aperture to which the scanner is set. Associated with scanners 1...N are sampling request detectors SRD consisting of differential amplifiers DA 1 and DA 2, a hold circuit and an aperture reference circuit. If in any one scanner the video signal reaches either one of the limits of the aperture,
i.e., when it terminates a run-length, a threshold device TD is caused by differential amplifier DA 1 to send a Request signal to the priority switch.

If only one such request is made at a time, the SRD requesting gets an Enable signal from the priority switch closing an analog switch AS within the SRD. The difference between the actual video signal and the hold value of the previous sample formed by differential amplifier DA 2 is sent to an A-D converter which receives only the magnitude after rectification. At the same time, the hold circuit is updated and a sign bit is produced.

Meanwhile, the address coder processes the Enable signal and supplies the enabled scanner's address to a parallel-to-series converter. This, in turn, transmits a code word composed of the address of the particular scanner, a sign bit and several bits for the magnitude of the sample taken.

At the receiver, th...