Low frequency digital comb filter system
First Claim
1. In a television signal processing system, including a source of sampled data video signals at a given data rate having first and second frequency interleaved signal components in a video passband, a comb filter system comprising:
- a first bandpass filter having an input responsive to said sampled data video signals and an output at which filtered signal samples occupying a portion of said video passband are produced at said given data rate;
a comb filter, responsive to said filtered signal samples, and operating at a reduced data rate which is less than said given data rate, for producing a comb filtered signal at said reduced data rate; and
a second bandpass filter responsive to said comb filtered signal for producing a comb filtered signal at said given data rate which occupies a portion of said video passband.
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Accused Products
Abstract
A comb filter arrangement operating at a reduced data rate is provided, which requires comparably fewer storage locations than previous arrangements. A digitized composite video signal of a given codeword rate is applied to a first bandpass filter, which produces a filtered signal restricted to a portion of the passband of the composite video signal. The filtered signal is then subsampled at a rate which satisfies the Nyquist criterion for information of the restricted passband. Codewords, now at a reduced data rate, are applied to a one-H delay line, and delayed and undelayed signals are combined to produce a first comb-filtered signal. The first comb-filtered signal is then applied to a second bandpass filter, which provides a sequence of codewords at the codeword rate of the original digitized composite video signal over a given frequency band. This sequence of codewords is then combined with the codewords of the composite video signal to produce a second comb-filtered signal.
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Citations
13 Claims
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1. In a television signal processing system, including a source of sampled data video signals at a given data rate having first and second frequency interleaved signal components in a video passband, a comb filter system comprising:
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a first bandpass filter having an input responsive to said sampled data video signals and an output at which filtered signal samples occupying a portion of said video passband are produced at said given data rate; a comb filter, responsive to said filtered signal samples, and operating at a reduced data rate which is less than said given data rate, for producing a comb filtered signal at said reduced data rate; and a second bandpass filter responsive to said comb filtered signal for producing a comb filtered signal at said given data rate which occupies a portion of said video passband. - View Dependent Claims (3)
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2. In a television signal processing system, including a source of sampled data video signals at a given data rate having first and second frequency interleaved signal components in a video passband, a comb filter system comprising:
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a first bandpass filter having an input responsive to said sampled data video signals and an output at which filtered signal samples occupying a portion of said video passband are produced at said given data rate; a comb filter, responsive to said filtered signal samples, and operating at a reduced data rate which is less than said given data rate, for producing a comb filtered signal at said reduced data rate; an interpolator having an input responsive to said comb filtered signal and an output at which a replica of said comb filtered signal is produced at said given data rate; and a second bandpass filter, coupled to the output signal at said given data rate for producing a comb filtered signal which occupies a portion of said video passband.
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4. In a television receiver, including a source of analog video signals occupying a given passband and containing first and second frequency interleaved signal components, a signal separation system comprising:
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an analog to digital converter responsive to said analog video signals for producing a sequence of digitized video signal samples in response to a sampling signal of a given frequency; a first bandpass filter having an input responsive to said digitized video signal sequence and an output at which a sequence of filtered video signal samples occupying a portion of said passband is produced at said given frequency; a first comb filter having an input responsive to selected ones of said filtered video signal samples and an output at which a first sequence of comb filtered signal samples is produced in a first phase relationship with said filtered video signal sample sequence; a second comb filter having an input responsive to selected ones of said filtered video signal samples and an output at which a second sequence of comb filtered signal samples is produced in a second phase relationship with said filtered video signal sample sequence; means for combining said first and second sequences of comb filtered signal samples to produce a first comb filtered signal corresponding to said first interleaved signal components; a second bandpass filter having an input responsive to said first comb filtered signal for producing a replica of said first comb filtered signal in a sequence of signal samples at said given frequency which occupies a portion of said passband; and a signal combining circuit having a first input responsive to said replica of said first comb filtered signal, a second input responsive to said sequence of digitized video signal samples produced by said analog to digital converter, and an output at which a second comb filtered signal corresponding to said second interleaved signal components is produced. - View Dependent Claims (5, 6, 7, 8, 9)
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10. Apparatus for comb filtering a sampled data composite signal of a given data rate including first and second frequency interleaved components comprising:
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a first comb filter responsive to every Nth signal sample for generating a first comb filtered signal where N is an integer; a second comb filter responsive to every Nth signal sample different from said samples in said first comb filter for generating a second comb filtered signal, said first and second comb filters operating at a lesser rate than the rate of said sampled data composite signal; means responsive to said first and second comb filtered signals for generating a third comb filtered signal at said sampled data composite signal rate, said third comb filtered signal corresponding to a combed manifestation of one of said first and second interleaved components; a bandpass filter responsive to said third comb filtered signal for passing a prescribed spectrum thereof; and means responsive to said sampled data composite signal and the signal produced by said bandpass filter for producing a fourth comb filtered signal wherein said fourth comb filtered signal and said third further signal correspond substantially exclusively to said first and said second frequency interleaved signal components respectively.
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11. In a television signal processing system, including a source of sampled data video signals at a given data rate having frequency interleaved luminance and chrominance signal components in a video passband, a signal separation arrangement comprising:
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a first bandpass filter having an input responsive to said sampled data video signals for producing a sequence of filtered signal samples occupying a portion of said passband; a comb filter, responsive to selected ones of said filtered signal samples for producing a comb filtered luminance signal at a reduced rate which is less than said given data rate; a second bandpass filter having an input responsive to said comb filtered luminance signal and an output at which a comb filtered luminance signal is produced at said given data rate which occupies a portion of said passband; and means, having a first input responsive to said comb filtered luminance signal produced by said second bandpass filter, a second input responsive to said sampled data video signals which occupy a portion of said video passband, and an output for producing a comb filtered luminance signal occupying said video passband. - View Dependent Claims (12, 13)
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Specification