Cbs Corporation

Marvin A Stern

John P Rossi

A system for reducing noise in a television signal utilizing integration and including a storage device for storing a television signal, and a summing device for adding a fractional amplitude portion of the signal stored in the storage device to a fractional amplitude portion of an incoming video signal, and operative automatically to change the fractional amplitude portion of the stored signal fed to the summing device as a function of the difference between stored and present signals, thereby to change the integration time constant of the system to accommodate for motion between the incoming signal and the stored frames, is improved by eliminating from the noise-reduced output signal troublesome transients caused by not changing at the appropriate time the fractional amplitude portion of the stored signals fed back to the summing device. This problem is overcome by generating in response to the difference between the incoming and stored video signals a gating waveform during the existence of which an increased portion of incoming video is coupled to the output of the system, delaying the incoming and stored video signals by an arbitrary amount sufficient to ensure that the onset of the gating waveform occurs sufficiently in advance of the delayed incoming and stored video signals as to be anticipatory of the delayed arriving and stored signals, and delaying the turn off or termination of the gating waveform thereby to delay the return to a condition of coupling a lower value of the fractional amplitude portion of the incoming video signal than occurred during the gating waveform.

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Stamford, CT, United States of America

Marvin A Stern