Patent US381986A successfully refreshed from Google Patents.
Patent EP0177320A2 successfully refreshed from Google Patents.
EP0177320A2
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Video signal digital processing system
Assignee: Victor Company of Japan Ltd
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Filing: 1985-09-30
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Granted: —
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Expires: 2005-09-30
Abstract
Abstract A video signal digital processing system comprises an A/D converter (12) for converting an input analog video signal employing the NTSC or PAL system into a digital video signal, a first converter (13, 14) for generating a signal sampled at a frequency f. which is a predetermined integer times a horizontal synchronizing signal frequency f H of the input analog video signal by frequency-converting the digital video signal so that the chrominance subcarrier frequency is converted into a frequency f s /4, a decimation circuit (15) for performing a 1/3 decimation process with respect to the output signal of the first converter by extracting samples with an interval of two samples, a processing circuit (16-18) for subjecting an output signal of the decimation circuit to a predetermined signal processing, an interpolation circuit (19, 20) for performing an interpolation process complementary to the decimation process with respect to an output signal of the processing circuit, a second converter (21) for subjecting an output signal of the interpolation circuit to a frequency conversion complementary to the frequency conversion performed in the first converter, and a D/A converter (22) for converting an output signal of the second converter into a an analog video signal.
Inventors
- 👤 Kaoru Kobayashi
- 👤 Hidetoshi Ozaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:23
CPC Classifications
H; H04; H04N; H04N11/00; H04N11/04; H04N9/00; H04N9/64
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
260 words
A video signal digital processing system characterized in that there are provided: an analog-to-digital converting means (12) for converting an input analog video signal employing the NTSC or PAL system into a digital video signal; first frequency converting means (13, 14) for generating a signal sampled at a sampling frequency f which is a predetermined integer times a horizontal synchronizing signal frequency f H of the input analog video signal by frequency-converting the output digital video signal of said analog-to-digital converting means, said first frequency converting means frequency-converting a chrominance subcarrier frequency of the digital video signal into a frequency f s/ 4; decimation means (15) for performing a 1/3 decimation process with respect to the output signal of said first frequency converting means by extracting samples in the output signal of said first frequency converting means with an interval of two samples; signal processing means (16, 17, 18) for subjecting an output signal of said decimation means to a predetermined signal processing; interpolation means (19, 20) for performing an interpolation process with respect to an output signal of said signal processing means, said interpolation process being a process complementary to said decimation process performed in said decimation means; second frequency converting means (21) for frequency-converting an output signal of said interpolation means, said second frequency converting means performing a frequency conversion complementary to the frequency conversion performed in said first frequency converting means; and digital-to-analog converting means (22) for generating an analog video signal by subjecting an output signal of said second frequency converting means to a digital-to-analog conversion.
Claim 2
Dependent Claim
260 words
A video signal digital processing system characterized in that there are provided: an analog-to-digital converting means (12) for converting an input analog video signal employing the NTSC or PAL system into a digital video signal; first frequency converting means (13, 14) for generating a signal sampled at a sampling frequency f which is a predetermined integer times a horizontal synchronizing signal frequency f H of the input analog video signal by frequency-converting the output digital video signal of said analog-to-digital converting means, said first frequency converting means frequency-converting a chrominance subcarrier frequency of the digital video signal into a frequency f s/ 4; decimation means (15) for performing a 1/3 decimation process with respect to the output signal of said first frequency converting means by extracting samples in the output signal of said first frequency converting means with an interval of two samples; signal processing means (16, 17, 18) for subjecting an output signal of said decimation means to a predetermined signal processing; interpolation means (19, 20) for performing an interpolation process with respect to an output signal of said signal processing means, said interpolation process being a process complementary to said decimation process performed in said decimation means; second frequency converting means (21) for frequency-converting an output signal of said interpolation means, said second frequency converting means performing a frequency conversion complementary to the frequency conversion performed in said first frequency converting means; and digital-to-analog converting means (22) for generating an analog video signal by subjecting an output signal of said second frequency converting means to a digital-to-analog conversion.
Claim 3
Dependent Claim
27 words
A video signal digital processing system as claimed in claim 1, characterized in that said predetermined integer is selected to 3M, where M is a positive integer.
Claim 4
Dependent Claim
106 words
A video signal digital processing system as claimed in claim 2, characterized in that there are further provided oscillator means (25) for generating a first clock signal having frequency equal to the sampling frequency f and frequency dividing means (26) for generating a second clock signal having a frequency f s /3 by frequency-dividing the first clock signal by 1/3, said decimation means comprising first latch means (57) for latching the output signal of said first frequency converting means responsive to the first clock signal and second latch means (58) for latching an output signal of said first latch means responsive to the second clock signal.
Claim 5
Dependent Claim
189 words
A video signal digital processing system as claimed in claim 2 which is applied to a magnetic recording and/or reproducing apparatus which successively records and/or reproduces signals on and/or from adjacent tracks on a magnetic tape, characterized in that said video signal digital processing system further comprises control means (27) supplied with an external mode discriminating signal indicating whether the magnetic recording and/or reproducing apparatus is in a recording mode or a reproducing mode, said control means in the recording mode controlling said first frequency converting means to perform a frequency conversion and a phase shift process in which the phase of the chrominance signal is shifted by 90° for every horizontal scanning period responsive to said external mode discriminating signal, said control means in the reproducing mode controlling said first frequency converting means to perform a frequency conversion and a demodulating process of the phase shift process responsive to said external mode discriminating signal, said signal processing means comprising a comb filter (18) which essentially does not operate in the recording mode but eliminates crosstalk components reproduced from adjacent tracks on the magnetic tape in the reproducing mode.
Claim 6
Dependent Claim
27 words
A video signal digital processing system as claimed in claim 1, characterized in that said predetermined integer is selected to 3M±1, where M is a positive integer.
Claim 7
Dependent Claim
189 words
A video signal digital processing system as claimed in claim 5 which is applied to a magnetic recording and/or reproducing apparatus which successively records and/or reproduces signals on and/or from adjacent tracks on a magnetic tape, characterized in that said video signal digital processing system further comprises control means (27) supplied with an external mode discriminating signal indicating whether the magnetic recording and/or reproducing apparatus is in a recording mode or a reproducing mode, said control means in the recording mode controlling said first frequency converting means to perform a frequency conversion and a phase shift process in which the phase of the chrominance signal is shifted by 90° for every horizontal scanning period responsive to said external mode discriminating signal, said control means in the reproducing mode controlling said second frequency converting means to perform a frequency conversion and a demodulating process of the phase shift process responsive to said external mode discriminating signal, said signal processing means comprising a comb filter (18) which essentially does not operate in the recording mode but eliminates crosstalk components reproduced from adjacent tracks on the magnetic tape in the reproducing mode.
Claim 8
Dependent Claim
88 words
A video signal digital processing system as claimed in claim 6, characterized in that said comb filter comprises adding means (68) supplied with an input signal of said comb filter, t90 0 phase shifting means (66) supplied with said input signal, delay means (67) for delaying an output of said phase shifting means, and switching means (SW) supplied with an output of said delay means, said switching means closing only in the reproducing mode so as to supply the output of said delay means to said adding means.
Claim 9
Dependent Claim
44 words
A video signal digital processing system as claimed in claim 7, characterized in that a combined delay time of said phase shifting means and said delay means is selected to one horizontal scanning period when said input composite video signal employs the NTSC system.
Claim 10
Dependent Claim
189 words
A video signal digital processing system as claimed in claim 5 which is applied to a magnetic recording and/or reproducing apparatus which successively records and/or reproduces signals on and/or from adjacent tracks on a magnetic tape, characterized in that said video signal digital processing system further comprises control means (27) supplied with an external mode discriminating signal indicating whether the magnetic recording and/or reproducing apparatus is in a recording mode or a reproducing mode, said control means in the recording mode controlling said first frequency converting means to perform a frequency conversion and a phase shift process in which the phase of the chrominance signal is shifted by 90° for every horizontal scanning period responsive to said external mode discriminating signal, said control means in the reproducing mode controlling said first frequency converting means to perform a frequency conversion and a demodulating process of the phase shift process responsive to said external mode discriminating signal, said signal processing means comprising a comb filter (18) which essentially does not operate in the recording mode but eliminates crosstalk components reproduced from adjacent tracks on the magnetic tape in the reproducing mode.
Claim 11
Dependent Claim
142 words
A video signal digital processing system as claimed in claim 9, characterized in that there are further provided oscillator means (25) for generating a first clock signal having a frequency equal to the sampling frequency f and frequency dividing means (26A) for frequency-dividing the first clock signal by 1/3 and for generating second through fourth clock signals having a frequency f s /3 but mutually differing in phase by 120°, said decimation means comprising data selector means (71) for selectively passing one of said second through fourth clock signals for every one horizontal scanning period, first latch means (72) for latching the output signal of said first frequency converting means responsive to said first clock signal, and second latch means (73) for latching an output signal of said first latch means responsive to an output clock signal of said data selector means.
Claim 12
Dependent Claim
92 words
A video signal digital processing system as claimed in claim 1, characterized in that said predetermined integer is selected to N, where N is an integer, and a number P described by P=r l +r 2 is an even number, where r l represents a remainder obtained by dividing N by four and r 2 represents a remainder obtained by dividing N by three, N=4K+r 1 , K is an integer, r l =O, 1, 2, or 3, N=3L+r 2 , L is an integer, and r 2 =0, +1, or -1.
Claim 13
Dependent Claim
189 words
A video signal digital processing system as claimed in claim 11 which is applied to a magnetic recording and/or reproducing apparatus which successively records and/or reproduces signals on and/or from adjacent tracks on a magnetic tape, characterized in that said video signal digital processing system further comprises control means (27) supplied with an external mode discriminating signal indicating whether the magnetic recording and/or reproducing apparatus is in a recording mode or a reproducing mode, said control means in the recording mode controlling said first frequency converting means to perform a frequency conversion and a phase shift process in which the phase of the chrominance signal is shifted by 90° for every horizontal scanning period responsive to said external mode discriminating signal, said control means in the reproducing mode controlling said first frequency converting means to perform a frequency conversion and a demodulating process of the phase shift process responsive to said external mode discriminating signal, said signal processing means comprising a comb filter (18) which essentially does not operate in the recording mode but eliminates crosstalk components reproduced from adjacent tracks on the magnetic tape in the reproducing mode.
Claim 14
Dependent Claim
91 words
A video signal digital processing system as claimed in claim 1, characterized in that said predetermined integer is selected to N, where N is an integer, and a number P described by P=r 1 + r 2 is an odd number, where r 1 represents a remainder obtained by dividing N by four and r 2 represents a remainder obtained by dividing N by three, N=4K+r,, K is an integer, r 1 =0, 1, 2, or 3, N=3Z+r 2 , L is an integer, and r 2 =0, +1, or -1.
Claim 15
Dependent Claim
189 words
A video signal digital processing system as claimed in claim 13 which is applied to a magnetic recording and/or reproducing apparatus which successively records and/or reproduces signals on and/or from adjacent tracks on a magnetic tape, characterized in that said video signal digital processing system further comprises control means (27) supplied with an external mode discriminating signal indicating whether the magnetic recording and/or reproducing apparatus is in a recording mode or a reproducing mode, said control means in the recording mode controlling said first frequency converting means to perform a frequency conversion and a phase shift process in which the phase of the chrominance signal is shifted by 90° for every horizontal scanning period responsive to said external mode discriminating signal, said control means in the reproducing mode controlling said second frequency converting means to perform a frequency conversion and a demodulating process of the phase shift process responsive to said external mode discriminating signal, said signal processing means comprising a comb filter (18) which essentially does not operate in the recording mode but eliminates crosstalk components reproduced from adjacent tracks on the magnetic tape in the reproducing mode.
References Cited (Backward Citations)
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