Apparatus for processing multiple asynchronous composite video signals

Claim 2

In a video signal processing system including a source of time-division multiplexed video signal having alternating first and second mutually independent composite video signal components each having luminance signal components and chrominance signal components including a color burst signal component, apparatus characterized by: means for generating a reference clock signal having a frequency substantially equal to an integral multiple of the frequency of the color burst signal component of said first composite video signal component; filtering means, responsive to said time-division multiplexed composite video signal for separating the chrominance signal components therefrom to provide a time-division multiplexed chrominance signal having alternating first and second chrominance signal components corresponding respectively to the respective chrominance components of said first and second composite video signal components; and phase correcting means, responsive to said time-division multiplexed chrominance signal, to said reference clock signal and to said color burst signal components for producing first and second phase corrected chrominance signals.

Claim 3

apparatus as set forth in claim 1 wherein said generating means includes a phase locked loop coupled to said source for causing said reference clock signal to have a predetermined phase relationship with respect to the color burst signal component of said first composite video signal component.

Claim 4

apparatus as set forth in claim 1 or 2 wherein the chrominance signal components of said first and second composite video signal components each include two quadrature phase related color difference signal components, said apparatus further comprising: means responsive to the burst signal component of said first and second phase corrected chrominance signals for determining values corresponding to the magnitudes of the burst signal components of the phase corrected chrominance signals; means responsive to the first and second phase corrected chrominance signals, to the values corresponding to the magnitudes of the first and second burst signal components and to a reference value, for providing first and second magnitude and phase corrected chrominance signals, the burst signal component of each having a magnitude substantially equal to said reference value; and means for separating each of the two quadrature phase related color difference signal components from each of said first and second magnitude and phase corrected chrominance signals.

Claim 5

Apparatus as set forth in claim 1 or 2 further including sampling means responsive to said time multiplexed composite video signal for providing samples representative thereof at instants determined by said reference clock signal, wherein said filtering means comprises: a comb filter coupled to said sampling means for providing a filtered output signal comprising samples representing a comb filtered chrominance components and part of the low frequency spectrum of the luminance signal component of said first composite video signal component; a multiplexer coupled to said sampling means and to said comb filter for providing, during alternate first and second time intervals, said filtered output signal and samples representing said second composite video signal component respectively; and band-pass filtering means coupled to said multiplexer for attenuating the luminance signal components relative to the chrominance signal components of the samples provided by said multiplexer to provide alternating first and second sequences of samples representing the chrominance components of said first and second composite video signals respectively.

Claim 6

Apparatus as set forth in claim 1 or 2 further including sampling means responsive to said time-division multiplexed composite video signal for providing samples representative thereof at instants determined by said reference clock signal, wherein said filtering means comprises: a comb filter coupled to said sampling means for providing luminance samples representing the luminance signal component of said first composite video signal component; and a low-pass filter coupled to said sampling means for providing samples representing the luminance signal component of said second composite video signal component.

Claim 7

Apparatus in accordance with claim 1 or 2 wherein said first and second composite video signal components respectively occur during alternate first and second time intervals, and the chrominance signal components of the respective composite video signal components each include two quadrature phase related color difference signal components, said apparatus further comprising: separating means, coupled to said filtering means and responsive to said time-division multiplexed chrominance signal for providing, during said first time intervals, two sequences of samples each corresponding to a respectively different one of the two color difference signal components of said first composite video signal and for providing, during said second time interval, two sequences of samples each corresponding to a respectively different one of the two color difference signal components of said second composite video signal.

Claim 8

Apparatus as set forth in claim 6 further comprising: an auxiliary memory, coupled to said separating means for storing color difference signal samples provided by said separating means during one of said second time intervals, and for providing said stored samples during a subsequent one of said first time intervals.

Claim 9

Apparatus as set forth in claim 6 or 7 further comprising: a main memory, coupled to said separating means for storing color difference samples provided by said separating means during one of said first time intervals and for providing said stored samples during a subsequent one of said second time intervals.

Claim 10

Apparatus as set forth in claim 6, 7 or 8 wherein said filtering means includes a comb filter providing, during said first intervals, a first output comprising comb filtered luminance samples of said first composite video signal and a second output comprising samples representing a comb filtered chrominance signal accompanied by part of the low frequency spectrum of the luminance signal components of said first composite video signal.

Claim 11

Apparatus as set forth in claim 9 wherein the comb filter comprises: memory means having an input port coupled to receive samples of said time-division multiplexed video signal, a number of sample delaying stages, and an output port for providing delayed samples of said first composite video signal during said first time intervals; first sample weighting means, coupled to said input port for multiplying the samples received thereby during said first time intervals by a selected one of a first set of predetermined weighting factors; second sample weighting means, coupled to the output port of said memory means for multiplying the samples provided thereby by a selected one of a second set of predetermined weighting factors; third sample weighting means, coupled to said input port for multiplying the samples received thereby during said first time intervals by a selected one of a third set of predetermined weighting factors; fourth sample weighting means, coupled to the output port of said memory means for multiplying the samples provided thereby by a selected one of a fourth set of predetermined weighting factors; first sample combining means coupled to said first and second sample weighting means for combining the samples provided thereby to produce said first output comprising said comb filtered luminance samples of said first composite video signal; and second sample combining means coupled to said third and fourth sample weighting means for combining the samples provided thereby to produce said first output including said comb filtered chrominance samples of said first composite video signal.