Cbs Corporation

James Kenneth Moore

William E Glenn, Jr

Arthur Kaiser

Method and apparatus for eliminating deadband effects in digital recursive filters caused by rounding of the quantization of products within the filter, wherein the product is represented by a digital word, consists of truncating the absolute value of the product-representing word to the next lower digit by dropping a number of least significant digits determined by the value of the multiplier and if any of the dropped digits is a 'one', adding a least significant 'one' to the truncated number while retaining the sign of the pre-truncated word, and repeating the process at the cycling frequency of the filter, until a steady state is reached at which the difference between the input and output of the filter becomes zero. The concept is described as embodied in a digital system utilizing a recursive filter for reducing noise in a color television signal.

Method and apparatus for eliminating deadband in digital recursive

A system for reducing noise in a color video signal which utilizes frame store integration and includes a delay or storage device for storing a single television frame, a summing device for adding a fractional amplitude portion of the signal stored in the storage device to a fractional amplitude portion of the present video signal, and a chrominance corrector circuit for altering the chrominance component of the stored signal so as to be in the proper phase relationship to be summed with the chrominance component of the present video signal. The system is operative automatically to change the fractional amplitude portion of the stored signal fed back 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 present signal and the stored frames. The system functions as a comb filter whose tines are very narrow when there is little or no motion between the present and stored frames and which are automatically widened to allow motion to be portrayed when there is relative motion between past and present signals.

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Springdale, CT, United States of America

James Kenneth Moore