US 4,123,774 A · Color signal encoding methods and apparatus for video recording and playback

A method of processing a color video signal in which quadrature modulated chroma information amplitude modulated at a first carrier frequency is translated to bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier, comprising the steps of:

(a) separating a signal representing said amplitude and quadrature modulated chroma information from said color video signal;
(b) applying said separated chroma information signal to one input of a first double balanced modulator;
(c) switching the phase of a reference source of said first carrier frequency alternately between zero degrees and ninety degrees from one horizontal video scan line to the next;
(d) mixing said phase switched first carrier reference with a reference source of said second carrier frequency to produce a signal comprising the sum and difference frequencies of said phase switched first carrier and said second carrier;
and
(e) applying said sum and difference frequency signal to a second input of said first double balanced modulator, whereby the output signal of said first double balanced modulator represents chroma information bisequentially amplitude modulated at said second carrier frequency with suppressed carrier.

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A method of processing a color video signal, in which bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier is translated to quadrature modulated chroma information amplitude modulated at a first carrier frequency, comprising the steps of:

(a) separating said bisequential chroma signal amplitude modulated with suppressed carrier from said color video signal;
(b) applying said separated chroma information signal to one input of a multiplier;
(c) switching the phase of a reference of said first carrier frequency between zero degrees and ninety degrees on adjacent horizontal video scan lines;
(d) mixing said phase switched first carrier reference with a reference of said second carrier frequency to produce a signal comprising the sum and difference frequencies of said phase switched first carrier and said second carrier;
(e) applying said sum and difference frequency signal to a second input of said multiplier, whereby the output signal of said multiplier represents bisequential chroma information amplitude modulated at said first carrier frequency with the carrier phase changing between zero and ninety degrees on adjacent horizontal video scan lines;
(f) delaying by one horizontal video scan line the output of said multiplier;
and
(g) additively combining the undelayed signal from said multiplier with the line delayed signal, whereby a quadrature and amplitude modulated chroma information signal is produced.

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An arrangement for processing a color video signal in which quadrature modulated chroma information amplitude modulated at a first carrier frequency is translated to bisequential chroma information amplitude modulated with suppressed carrier, comprising:

(a) means for separating from said color video signal a signal representing said amplitude and quadrature modulated chroma information;
(b) means for producing a reference signal at said first carrier frequency switched in phase between 0.degree. and 90.degree. on adjacent horizontal video scan lines;
(c) means for producing a reference signal at said second carrier frequency;
(d) means coupled for mixing said phase-switched first carrier frequency signal and said second carrier frequency signal to produce a signal comprising a sum and difference frequency signal;
and
(e) means coupled for double balanced modulating said sum and difference signal with said quadrature and amplitude modulated chroma information signal, whereby an output signal representing bisequential chroma information amplitude modulated with suppressed carrier is produced.

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An arrangement for processing a color video signal, in which bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier is translated to quadrature modulated chroma information amplitude modulated at a first carrier frequency, comprising:

(a) means coupled for separating said bisequential chroma signal from said color video signal;
(b) means coupled for producing a reference signal at said first carrier frequency phase switched between zero degrees and ninety degrees on adjacent horizontal video scan lines;
(c) means coupled for producing a reference signal at said second carrier frequency;
(d) means coupled for mixing said phase switched first carrier frequency signal and said second carrier frequency signal to produce a sum and difference frequency signal;
(e) means coupled for multiplying said bisequential chroma signal amplitude modulated at said second carrier frequency with suppressed carrier by said sum and difference frequency signal to produce an output signal representing bisequential chroma information amplitude modulated at said first carrier frequency with the carrier phase angle changing between zero degrees and ninety degrees on adjacent horizontal video scan lines;
(f) means for delaying by one horizontal video scan line the output of said multiplying means;
and
(g) means for additively combining the undelayed signal from said multiplying means with the line delayed signal, whereby a quadrature and amplitude modulated chroma information signal is produced.

5 more elements

A method of processing a color video signal in which quadrature modulated chroma information amplitude modulated at a first carrier frequency is translated to bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier, comprising the steps of:

(a) separating a signal representing said amplitude and quadrature modulated chroma information from said color video signal;
(b) switching the phase angle of a reference source of said first carrier frequency alternately between 0.degree. and 90.degree. on adjacent horizontal video scan lines;
(c) double balanced modulating said amplitude and quadrature modulated chroma signal with the phase switched first carrier frequency to produce an unmodulated bisequential chroma signal;
(d) double balanced modulating said unmodulated bisequential chroma signal with a reference source of said second carrier frequency to produce a bisequential chroma signal amplitude modulated with suppressed carrier at said second carrier frequency;
(e) separating a signal representing luma information from said color video signal;
(f) frequency modulating said luma signal at a third carrier frequency, said third carrier frequency being substantially lower than said second carrier frequency and being selected so that sidebands of the bisequential chroma signal amplitude modulated with suppressed carrier will not appreciably interfere with sidebands of the frequency modulated luma signal;
and
(g) additively combining the bisequential chroma signal amplitude modulated with suppressed carrier and the frequency modulated luma signal to produce an output signal:

5 more elements

A method of processing a color video signal, in which bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier is translated to quadrature modulated chroma information amplitude modulated at a first carrier frequency, comprising the steps of:

(a) separating a representing bisequential chroma information amplitude modulated with suppressed carrier from said color video signal;
(b) double balanced modulating said bisequential chroma signal amplitude modulated with suppressed carrier, with a reference source of said second carrier frequency to produce an unmodulated bisequential chroma signal;
(c) switching the phase angle of a reference source of said first carrier frequency alternately between 0.degree. and 90.degree. on adjacent horizontal video scan lines;
(d) double balanced modulating said unmodulated bisequential chroma signal with the phase switched first carrier frequency to produce a bisequential amplitude and quadrature modulated chroma signal;
(e) delaying by one horizontal video scan line the said bisequential amplitude and quadrature modulated chroma signal;
(f) additively combining the undelayed and the delayed bisequential amplitude and quadrature modulated chroma signal to produce a simultaneous quadrature and amplitude modulated chroma signal;
(g) separating a signal representing frequency modulated luma information from said color video signal;
(h) frequency demodulating said separated luma signal;
and
(i) additively combining the unmodulated luma signal and said simultaneous quadrature and amplitude modulated chroma signal.

7 more elements

An arrangement for processing a color video signal in which quadrature modulated chroma information amplitude modulated at a first carrier frequency is translated to bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier, comprising:

(a) means coupled for separating a signal representing said amplitude and quadrature modulated chroma information from said color video signal;
(b) means coupled for switching the phase angle of a reference source of said first carrier frequency between 0.degree. and 90.degree. on adjacent horizontal video scan lines;
(c) means coupled for double balanced modulating said amplitude and quadrature modulated chroma signal with the phase switched first carrier frequency to produce an unmodulated bisequential chroma signal;
(d) means coupled for double balanced modulating said unmodulated bisequential chroma signal with a reference source of said second carrier frequency to produce a bisequential chroma signal amplitude modulated with suppressed carrier at said second carrier frequency;
(e) means coupled for separating a signal representing luma information from said color video signal;
(f) means coupled for frequency modulating said luma signal at a third carrier frequency, said third carrier frequency being substantially lower than said second carrier frequency and being selected so that sidebands of the bisequential chroma signal amplitude modulated with suppressed carrier will not appreciably interfere with sidebands of the frequency modulated luma signal;
and
(g) means coupled for additively combining the bisequential chroma signal amplitude modulated with suppressed carrier and the frequency modulated luma signal to produce an output signal.

5 more elements

An arrangement for processing a color video signal, in which bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier is translated to quadrature modulated chroma information amplitude modulated at a first carrier frequency, comprising:

(a) means coupled for separating a signal representing bisequential chroma information amplitude modulated with suppressed carrier from said color video signal;
(b) means coupled for double balanced modulating said bisequential chroma signal amplitude modulated with suppressed carrier, with a reference source of said second carrier frequency, to produce an unmodulated bisequential chroma signal;
(c) means coupled for switching the phase angle of a reference source of said first carrier frequency alternately between zero and ninety degrees on adjacent horizontal video scan lines;
(d) means coupled for double balanced modulating said unmodulated bisequential chroma signal with the phase switched first carrier frequency to produce a bisequential amplitude and quadrature modulated chroma signal;
(e) means coupled for delaying by one horizontal video scan line said bisequential amplitude and quadrature modulated chroma signal;
(f) means coupled for additively combining the undelayed and the delayed bisequential amplitude and quadrature modulated chroma signal to produce a simultaneous quadrature and amplitude modulated chroma signal;
(g) means coupled for separating a signal representing frequency modulated luma information from said color video signal;
(h) means coupled for frequency demodulating said separated luma signal;
and
(i) means coupled for additively combining said unmodulated luma signal and said quadrature and amplitude modulated chroma signal.

7 more elements

A method for processing a color video signal in which bisequential chroma information frequency modulated at a first carrier frequency is translated to bisequential chroma information amplitude modulated at a second carrier frequency, comprising the steps of:

(a) separating a signal representing said bisequential frequency modulated chroma information from said color video signal;
(b) frequency demodulating said bisequential frequency modulated chroma signal;
(c) double balanced modulating the demodulated bisequential chroma signal with a reference source of said second carrier frequency to produce a bisequential chroma signal amplitude modulated with suppressed carrier at said second carrier frequency;
(d) separating a signal representing luma information from said color video signal;
(e) frequency modulating said luma signal at a third carrier frequency, said third carrier frequency being substantially lower than said second carrier frequency and being selected so that sidebands of the bisequential chroma signal amplitude modulated with suppressed carrier will not appreciably interfere with sidebands of the frequency modulated luma signal;
and
(f) additively combining the bisequential chroma signal amplitude modulated with suppressed carrier and the frequency modulated luma signal to produce an output signal.

4 more elements

A method of processing a color video signal, in which bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier is translated to bisequential chroma information frequency modulated at a first carrier frequency, comprising the steps of:

(a) separating a signal representing bisequential chroma information amplitude modulated with suppressed carrier from said color video signal
(b) double balanced modulating said bisequential chroma signal amplitude modulated with suppressed carrier, with a reference source of said second carrier frequency, to produce an unmodulated bisequential chroma signal;
(c) frequency modulating said unmodulated bisequential chroma signal at said first carrier frequency;
(d) separating a signal representing frequency modulated luma information from said color video signal;
(e) frequency demodulating said separated luma signal;
and
(f) additively combining the unmodulated luma signal and the frequency modulated bisequential chroma signal.

4 more elements

An arrangement for processing a color video signal, in which bisequential chroma information frequency modulated at a first carrier frequency is translated to bisequential chroma information amplitude modulated at a second carrier frequency, comprising:

(a) means coupled for separating a signal representing said bisequential frequency modulated chroma information from said color video signal;
(b) means coupled for frequency demodulating said bisequential frequency modulated chroma signal;
(c) means coupled for double balanced modulating the demodulated bisequential chroma signal with a reference source of said second carrier frequency to produce a bisequential chroma signal amplitude modulated with suppressed carrier at said second carrier frequency;
(d) means coupled for separating a signal representing luma information from said color video signal;
(e) means coupled for frequency modulating said luma signal at a third carrier frequency, said third carrier frequency being substantially lower than said second carrier frequency and being selected so that sidebands of the bisequential chroma signal amplitude modulated with suppressed carrier will not appreciably interfere with sidebands of the frequency modulated luma signal;
and
(f) means coupled for additively combining the bisequential chroma signal amplitude modulated with suppressed carrier and the frequency modulated luma signal to produce an output signal.

4 more elements

An arrangement for processing a color video signal, in which bisequential chroma information amplitude modulated at a second carrier frequency with suppressed carrier is translated to bisequential chroma information frequency modulated at a first carrier frequency, comprising:

(a) means coupled for separating a signal representing bisequential chroma information amplitude modulated with suppressed carrier from said color video signal;
(b) means coupled for double balanced modulating said bisequential chroma signal amplitude modulated with suppressed carrier, with a reference source of said second carrier frequency, to produce an unmodulated bisequential chroma signal;
(c) means coupled for frequency modulating said unmodulated bisequential chroma signal at said first carrier frequency;
(d) means coupled for separating a signal representing frequency modulated luma information from said color video signal;
(e) means coupled for frequency demodulating said separated luma signal;
and
(f) means coupled for additively combining the unmodulated luma signal and the frequency modulated bisequential chroma signal.

4 more elements

Color signal encoding methods and apparatus for video recording and playback

Life of this patent

Color signal encoding methods and apparatus for video recording and playback

Life of this patent

Abstract

Claims134