Patent US3798361A successfully refreshed from Google Patents.
US3798361A
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US
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Magnetic recording and/or reproducing system
Assignee: Sony Corp
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Filing: 1972-11-22
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Granted: 1974-03-19
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Expires: 1992-11-22
Abstract
Abstract An improved system for magnetic recording and/or reproducing a color television signal including a luminance signal and a chrominance signal which contains a burst signal therein. Before recording the television signal, the chrominance signal is frequency-converted to a frequency band lower than its original one and the burst signal is extracted from the chrominance signal. The burst signal is then amplitude modulated by a rectangular waveform signal, derived from the horizontal synchronization signal, whose frequency is equal to two scanning line periods. The amplitude modulated burst signal is combined with the luminance signal to frequency-modulate a carrier signal having a predetermined frequency. The frequency-converted chrominance signal is gated by the rectangular wave signal and recorded along with the frequency-modulated signal on a magnetic medium. When the magnetic medium is played back, the frequencyconverted chrominance signal is frequency-reconverted to the original frequency band by means of a reference signal the phase of which is controlled by the burst signal reproduced by frequency-demodulation so that phase errors of the reproduced chrominance signal are diminished. The frequency-reconverted chrominance signal is then gated by a rectangular waveform signal derived by detecting the amplitude modulation of the reproduced, frequency demodulated burst signal. The gated, frequencyreconverted chrominance signal is then combined with a portion of the same signal delayed by one scanning line period to produce a continuous chrominance signal.
Inventors
- 👤 Y Watanabe
- 👤 H Narahara
- 👤 T Numakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:17
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/86
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
183 words
A system for magnetic recording of a composite color television signal having a first band containing a luminance signal and a second band containing chrominance and burst signals, and being divided into intervals including field, line, and blanking intervals, wherein the system comprises: a. means for separating the luminance signal and the chrominance signal from the composite color television signal; b. means for frequency-converting the separated chrominance signal to a frequency band lower than its original one; c. means for extracting the burst signals from the frequencyconverted chrominance signal; d. means for amplitude modulating the extracted burst signals such that successive, alternate burst signals have a first and a second predetermined amplitudes, respectively; e. means for combining the separated luminance signal and the amplitude modulated burst signals into a combined signal; f. means for frequency-modulating a carrier signal with the combined signal to produce a frequency-modulated signal; g. means for gating alternating, substantially equal intervals of the chrominance signal component; h. means for combining the frequency-modulated signal and the frequency-converted, gated chrominance signal and for recording both of them on a magnetic mediuM.
Claim 2
Independent Claim
183 words
A system for magnetic recording of a composite color television signal having a first band containing a luminance signal and a second band containing chrominance and burst signals, and being divided into intervals including field, line, and blanking intervals, wherein the system comprises: a. means for separating the luminance signal and the chrominance signal from the composite color television signal; b. means for frequency-converting the separated chrominance signal to a frequency band lower than its original one; c. means for extracting the burst signals from the frequencyconverted chrominance signal; d. means for amplitude modulating the extracted burst signals such that successive, alternate burst signals have a first and a second predetermined amplitudes, respectively; e. means for combining the separated luminance signal and the amplitude modulated burst signals into a combined signal; f. means for frequency-modulating a carrier signal with the combined signal to produce a frequency-modulated signal; g. means for gating alternating, substantially equal intervals of the chrominance signal component; h. means for combining the frequency-modulated signal and the frequency-converted, gated chrominance signal and for recording both of them on a magnetic mediuM.
Claim 3
Dependent Claim
199 words
A system for magnetic recording as recited in claim 1 including, in addition, reproducing means to reproduce the signals recorded on the magnetic medium, the reproducing means comprising: a. magnetic transducer means for converting the magnetic signals representing the frequency-modulated signal and the recorded intervals of the frequency-converted chrominance signal on the magnetic medium into corresponding electrical signals; b. means for frequency-demodulating the frequency-modulated electrical signal to produce the combined luminance signal and the frequency converted burst signals; c. means for extracting the frequency-converted burst signals from the combined signal; d. means for generating a reference signal to be used for frequency-reconverting the chrominance electrical signal component; e. means for supplying the extracted burst signals to the reference signal generating means to control the phase of the reference signal; f. means for frequency-reconverting the recorded intervals of the chrominance electrical signal component with the reference signal to the original frequency band of the chrominance signal; g. means for delaying the recorded intervals of the chrominance electrical signal component to form delayed replicas of the recorded intervals, and h. means for combining the recorded intervals of the chrominance electrical signals and the delayed replicas to form a continuous chrominance signal.
Claim 4
Dependent Claim
27 words
A system for magnetic recording as recited in claim 1, wherein the frequency-converting means is connected to the gating means for gating the frequency-converted chrominance signal component.
Claim 5
Dependent Claim
60 words
A system for magnetic recording as recited in claim 3, wherein the gating means is responsive to the means for amplitude modulating the burst signals such that it gates alternate line intervals of the frequency-converted chrominance signal and passes the frequency-converted chrominance signal only during line intervals in which the burst signal is modulated to have the first predetermined amplitude.
Claim 6
Dependent Claim
81 words
A system for magnetic recording as recited in claim 4 wherein the composite color television signal further contains a horizontal synchronization signal occuring at regular periods and the means for amplitude modulating the burst signals comprises means for separating the horizontal synchronization signal from the composite color television signal and for generating a rectangular wave shaped gating signal which is synchronized with the horizontal synchronization signal and whose period is substantially equal to twice the period of the horizontal synchronization signal.
Claim 7
Dependent Claim
33 words
A system for magnetic recording as recited in claim 5 wherein the rectangular wave shaped signal alternates between a third and a fourth predetermined amplitude in synchronization with successive, alternate, horizontal synchronization pulses.
Claim 8
Independent Claim
210 words
A system for reproducing a color television signal from a recorded signal that includes a carrier which is frequency modulated by a combined signal of a luminance signal and amplitude modulated, frequency-converted burst signals, and a frequency-converted chrominance signal which is gated in response to the amplitudes of the burst signals, the system comprising: a. transducer means for converting the recorded signal into corresponding electrical signals; b. means for separating the frequency-modulated signal from the frequency-converted chrominance signal; c. means for frequency-demodulating the frequency-modulated signal to obtain the luminance signal and the frequency-converted burst signals; d. means for generating a reference signal, including means for controlling the phase of the reference signal by the frequency-converted burst signals; e. means for utilizing the reference signal to frequency-reconvert the frequency-converted chrominance signal; f. means for amplitude detecting the frequency-converted burst signal to produce a gating signal which is synchronized with tHe frequency-converted burst signals and has a period which is substantially equal to twice the interval period between successive frequency-converted burst signals; g. means responsive to the gating signal for gating the frequency-reconverted chrominance signal; h. means for combining the gated, frequency-reconverted chrominance signal with the luminance signal to produce a color television signal representative of an original composite color television signal.
Claim 9
Independent Claim
210 words
A system for reproducing a color television signal from a recorded signal that includes a carrier which is frequency modulated by a combined signal of a luminance signal and amplitude modulated, frequency-converted burst signals, and a frequency-converted chrominance signal which is gated in response to the amplitudes of the burst signals, the system comprising: a. transducer means for converting the recorded signal into corresponding electrical signals; b. means for separating the frequency-modulated signal from the frequency-converted chrominance signal; c. means for frequency-demodulating the frequency-modulated signal to obtain the luminance signal and the frequency-converted burst signals; d. means for generating a reference signal, including means for controlling the phase of the reference signal by the frequency-converted burst signals; e. means for utilizing the reference signal to frequency-reconvert the frequency-converted chrominance signal; f. means for amplitude detecting the frequency-converted burst signal to produce a gating signal which is synchronized with tHe frequency-converted burst signals and has a period which is substantially equal to twice the interval period between successive frequency-converted burst signals; g. means responsive to the gating signal for gating the frequency-reconverted chrominance signal; h. means for combining the gated, frequency-reconverted chrominance signal with the luminance signal to produce a color television signal representative of an original composite color television signal.
Claim 10
Dependent Claim
81 words
A system as recited in claim 7, wherein the reference signal generating means comprises: a. an oscillator for generating a constant frequency signal; b. a phase detector for comparing the phase of the constant frequency signal with the phase of the frequency-reconverted burst signal; c. a variable frequency oscillator controlled by the output of the phase detector; and d. a frequency converter responsive to the phase detector output for converting the frequency of the constant frequency signal into the reference signal.
Claim 11
Dependent Claim
43 words
A system as recited in claim 7 further comprising means for delaying the gated, frequency-reconverted chrominance signal to form delayed replicas thereof and means for combining the gated, frequency-reconverted chrominance signal with the delayed replicas thereof to form a substantially continuous chrominance signal.
Claim 12
Dependent Claim
110 words
A system as recited in claim 9 wherein the recorded, frequency-modulated combined signal further includes horizontal synchronization signals and the means for producing a gating signal further comprises means for extracting the horizontal synchronization signals from the frequency-demodulated combined signal, means responsive to the amplitude of the frequency-converted burst signals for producing an amplitude detected signal, and means responsive to the amplitude detected signal and the horizontal synchronization signals for producing the gating signal to have a rectangular wave form with a period which is substantially equal to the combined periods between two successive horizontal synchronization signals and having an amplitude determined by the amplitudes of the frequency-converted burst signals.
References Cited (Backward Citations)
US3626087A
Cited
US3728477A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |