US3896487A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compatible stereoscopic color television system
Assignee: Individual
•
Filing: 1973-08-02
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Granted: 1975-07-22
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Expires: 1993-08-02
Abstract
Abstract A compatible stereoscopic colour television system with phasedifference quadrature modulation of the colour subcarrier by the chrominance signals of the first image of the stereo pair and transmission of the signals of the second image of the stereo pair on a subcarrier located in the frequency spectrum of the luminance signal, according to the invention, the system is characterized by the fact that the luminance signal of the second image of the stereo pair is employed for effecting additional modulation of the subcarrier so that the amplitude of the latter in one line is equal to the sum of the amplitude of the modulating signal and the square root from the amplitude of thel quadrature modulated subcarrier, whereas in the other line it is equal to the difference of these amplitudes; the additional modulation is carried out with conservation of the phase difference of the subcarrier in the adjacent lines; during the reception the chrominance signals of the first image of the stereo pair are separated by way of multiplying the delayed and undelayed voltages of the subcarrier directly for one signal and with an additional 90* phase shift for the other signal, the chrominance signals of the second image of the stereo pair being separated by way of detecting the delayed and undelayed voltages and obtaining the difference of their envelopes.
Inventors
- 👤 Vladimir Efimovich Tesler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:15
CPC Classifications
H; H04; H04N; H04N13/00; H04N13/10; H04N13/194; H04N13/106; H04N13/156; H04N13/161
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
197 words
A compatible stereoscopic color television system with phasedIfference quadrature modulation of the color subcarrier in the frequency spectrum of the luminance signal by chrominance signals of the first image of the stereo pair and transmission of the signals of the second image of the stereo pair on the same subcarrier by its additional modulation by the luminance signals of the second image of the stereo pair so that the amplitude of the subcarrier in one line is equal to the sum of the amplitude of the modulating signal and the square root from the amplitude of the quadrature modulated subcarrier, and in the other line it is equal to the difference of said amplitudes, said additional modulation being effected to preserve the difference of the subcarrier phases in adjacent lines, during reception chrominance signals of said first image of the stereo pair being separated by multiplying the delayed and undelayed voltages of the subcarrier directly for one signal and with an additional 90* phase shift therebetween for the other signal, the chrominance signals of the second image of the stereo pair being separated by detecting the delayed and undelayed voltages and obtaining the difference of their envelopes.
Claim 2
Dependent Claim
197 words
A compatible stereoscopic color television system with phasedIfference quadrature modulation of the color subcarrier in the frequency spectrum of the luminance signal by chrominance signals of the first image of the stereo pair and transmission of the signals of the second image of the stereo pair on the same subcarrier by its additional modulation by the luminance signals of the second image of the stereo pair so that the amplitude of the subcarrier in one line is equal to the sum of the amplitude of the modulating signal and the square root from the amplitude of the quadrature modulated subcarrier, and in the other line it is equal to the difference of said amplitudes, said additional modulation being effected to preserve the difference of the subcarrier phases in adjacent lines, during reception chrominance signals of said first image of the stereo pair being separated by multiplying the delayed and undelayed voltages of the subcarrier directly for one signal and with an additional 90* phase shift therebetween for the other signal, the chrominance signals of the second image of the stereo pair being separated by detecting the delayed and undelayed voltages and obtaining the difference of their envelopes.
Claim 3
Dependent Claim
84 words
A compatible system according to claim 1, wherein to ensure the transmission of information about the color of the second image of the stereo pair, an additional subcarrier is inserted into the frequency spectrum of said luminance signal of said image and quadrature modulated by two color-difference signals by the NTSC method, during reception the voltage of the modulated additional subcarrier is separated from the difference signal of the envelopes of the fundamental subcarrier by a bandpass filter and detected synchronously in two channels.
Claim 4
Dependent Claim
77 words
A compatible system according to claim 2, wherein to simplify the regeneration of the color-difference signals of the second image of the stereo pair, the frequency of said additional subcarrier is selected to be equal to half the frequency of the fundamental subcarrier, during reception a reference signal is shaped for synchronous detection of the modulated additional subcarrier by dividing the frequency of the signal of the modulated fundamental subcarrier from the lines with a reference phase.
Claim 5
Dependent Claim
86 words
A compatible system according to claim 1, wherein to reduce the level of cross-talk from the additional signal, the voltage of said luminance signal of the second image of the stereo pair is converted, before said signal modulates the subcarrier, into a bipolar voltage, for which purpose additional pulses having an amplitude equal to half the amplitude of the luminance signal are inserted into said signal, in the interval of the line blanking pulses, and the level is clamped to the tops of said additional pulses.
Claim 6
Dependent Claim
125 words
A compatible system according to claim 1, wherein to ensure the transmission of information about the color of the second image of the stereo pair, an additional subcarrier is inserted into the frequency spectrum of said luminance signal of said image and quadrature modulated by two color-difference signals, and wherein to improve the efficiency of protection of the signals of the additional subcarrier against the effects of distortions of the differential phase and parasitic suppression of one modulation sidebands types, the quadrature modulation of the additional subcarrier is performed with the reversal of polarity of one of the color-difference signals from line to line by the PAL method while during reception the color-difference signals of the second image of the stereo pair are regenerated correspondingly.
Claim 7
Dependent Claim
70 words
A compatible system according to claim 1, wherein to improve the immunity of the system to distortions of the differential phase type of the signals of said additional subcarrier and to improve the quality of color reproduction, the modulation of said additional color subcarrier is effected by relative quadrature modulation by the NIIR method, during reception the color-difference signals of the second image of the stereo pair are regeneRated correspondingly.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |