US4245234A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of recording color television signals as a repetitive series of normally recorded lines and phase reversed lines
Assignee: US Philips Corp
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Filing: 1978-11-13
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Granted: 1981-01-13
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Expires: 1998-11-13
Abstract
Abstract For recording and/or reproducing color television signals steps are proposed which enable the crosstalk signal from an adjacent track to be suppressed during reproduction. This is possible both for the chrominance signal and for the luminance signal. For this purpose the polarity of the signals in the line periods in all tracks is switched during recording in periodically recurrent groups with the same pattern of consecutive polarities, the groups comprising at least four line periods and being offset relative to each other in adjacent tracks by at least one line period. During reproduction the signals scanned from the relevant track whose polarities have been switched, at least in respect of the chrominance signal, are restored to signals with the original polarities. The frequency spectra of the useful signal relative to the crosstalk signal from an adjacent track are then interlaced, which is utilized for suppressing the crosstalk signal.
Inventors
- 👤 Harald E. Melwisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:49
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/82; H04N9/83; H04N9/84
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
213 words
An improved method of recording color television signals in accordance with which the individual line period sectors in adjoining tracks on the record carrier are aligned relative to each other in a direction perpendicular to the tracks, and wherein in at least one of two adjoining tracks the polarity of the signals to be recorded, which are modulated on a carrier, is switched periodically in the line periods, while for signals which exhibit maxima in the frequency spectrum at distances corresponding to half the line frequency the signals of two consecutive line periods in a track relative to the two line periods adjoining these in an adjacent track exhibit alternately in pairs the same and different polarities, and for signals which exhibit maxima in the frequency spectrum at distances corresponding to the whole line frequency, the signals of the individual consecutive line periods in adjacent tracks alternately exhibit the same and different polarities with respect to each other, the improvement being characterized in that in all tracks the polarities of the signals in the line periods are switched in periodically recurring groups with the same pattern of consecutive polarities, the groups comprising at least four line periods, and are offset relative to each other by at least one line period in adjacent tracks.
Claim 2
Dependent Claim
213 words
An improved method of recording color television signals in accordance with which the individual line period sectors in adjoining tracks on the record carrier are aligned relative to each other in a direction perpendicular to the tracks, and wherein in at least one of two adjoining tracks the polarity of the signals to be recorded, which are modulated on a carrier, is switched periodically in the line periods, while for signals which exhibit maxima in the frequency spectrum at distances corresponding to half the line frequency the signals of two consecutive line periods in a track relative to the two line periods adjoining these in an adjacent track exhibit alternately in pairs the same and different polarities, and for signals which exhibit maxima in the frequency spectrum at distances corresponding to the whole line frequency, the signals of the individual consecutive line periods in adjacent tracks alternately exhibit the same and different polarities with respect to each other, the improvement being characterized in that in all tracks the polarities of the signals in the line periods are switched in periodically recurring groups with the same pattern of consecutive polarities, the groups comprising at least four line periods, and are offset relative to each other by at least one line period in adjacent tracks.
Claim 3
Dependent Claim
100 words
A method as claimed in claim 1, characterized in that the groups extend continuously over the adjacent tracks without interruption of the pattern, in compliance with the requirement z+n-x g-k=0 where z is the number of line periods in one track, n the number of line periods corresponding to a line offset between adjacent tracks at the beginning and at the end, g the number of line periods in a group, x an integer smaller than z divided by g, and k the number of line periods by which the groups in adjoining tracks are offset relative to each other.
Claim 4
Dependent Claim
46 words
A method as claimed in claim 1, characterized in that for an adaptation of the patterns of the consecutive polarities at the transition from one track to the next track a phase shift is introduced in the polarity switching of the signals in the line periods.
Claim 5
Independent Claim
60 words
A method as claimed in any one of the preceding claims, characterized in that for the signals to be recorded, which have been modulated on a carrier, the polarity of the signals in the line periods is switched both for the signals which transmit the chrominance information and for those which transmit the luminance information of the color television signals.
Claim 6
Dependent Claim
85 words
A method as claimed in claim 4, characterized in that it in the case of color television signals in which the signals to be recorded, which are modulated on a carrier, and which transmit the chrominance information and the luminance information of the color television signals, both exhibit maxima in the frequency spectrum at distances of the whole line frequency, the polarity of the signals in the line periods is switched jointly for both these signals, in equal groups with equal patterns of consecutive polarities.
Claim 7
Dependent Claim
54 words
A method of reproducing signals recorded in accordance with a method as claimed in claim 5, characterized in that of the signals whose polarity has been switched and which have been scanned from the relevant track, at least those signals, which are quadrature-modulated on a carrier, are restored to signals with the original polarity.
Claim 8
Dependent Claim
45 words
A method as claimed in claim 6, characterized in that the signals scanned from the relevant track, whose polarities have been switched are directly restored to signals with the original polarity, after which the signals transmitting the chrominance information the luminance information are further processed.
Claim 9
Independent Claim
311 words
An apparatus for the recording and/or playback of color television signals of the type where individual line period sectors are recorded in adjoining tracks and are aligned relative to each other in a direction perpendicular to the tracks, wherein in at least one of two adjoining tracks the polarity of signals modulated on a carrier to be recorded is switched periodically in the line periods, while for signals exhibiting maxima in the frequency spectrum at distances corresponding to half the line frequency the signals of two consecutive line periods in a track relative to the two line periods adjoining these in an adjacent track exhibit alternately in pairs the same and different polarities, and for signals exhibiting maxima in the frequency spectrum at distances corresponding to the whole line frequency the signals of individual consecutive line periods in adjacent tracks alternately exhibit the same and different polarities with respect to each other, wherein in all tracks the polarities of the signals in the line periods are switched in periodically recurring groups with the same pattern of consecutive polarities, the groups comprising at least four line periods offset relative to each other by at least one line period in adjacent tracks, said apparatus comprising at least one device for switching the polarity of the signals in line periods, a control device means for controlling said switching means and receiving at least one signal of line synchronizing frequency, the control device comprising a counter which receives the signal of line synchronizing frequency at an input and having a number of counter positions equal to the number of line periods in a group, a decoding device connected to the counter and programmed in accordance with the pattern of consecutive polarities in a group and at whose output a control signal for the polarity-switching device is available, with said signal in conformity with said pattern.
Claim 10
Independent Claim
311 words
An apparatus for the recording and/or playback of color television signals of the type where individual line period sectors are recorded in adjoining tracks and are aligned relative to each other in a direction perpendicular to the tracks, wherein in at least one of two adjoining tracks the polarity of signals modulated on a carrier to be recorded is switched periodically in the line periods, while for signals exhibiting maxima in the frequency spectrum at distances corresponding to half the line frequency the signals of two consecutive line periods in a track relative to the two line periods adjoining these in an adjacent track exhibit alternately in pairs the same and different polarities, and for signals exhibiting maxima in the frequency spectrum at distances corresponding to the whole line frequency the signals of individual consecutive line periods in adjacent tracks alternately exhibit the same and different polarities with respect to each other, wherein in all tracks the polarities of the signals in the line periods are switched in periodically recurring groups with the same pattern of consecutive polarities, the groups comprising at least four line periods offset relative to each other by at least one line period in adjacent tracks, said apparatus comprising at least one device for switching the polarity of the signals in line periods, a control device means for controlling said switching means and receiving at least one signal of line synchronizing frequency, the control device comprising a counter which receives the signal of line synchronizing frequency at an input and having a number of counter positions equal to the number of line periods in a group, a decoding device connected to the counter and programmed in accordance with the pattern of consecutive polarities in a group and at whose output a control signal for the polarity-switching device is available, with said signal in conformity with said pattern.
Claim 11
Dependent Claim
134 words
An apparatus as claimed in claim 8, wherein from an adaption of the patterns of the consecutive polarities at the transition from one track to the next track a phase shift is introduced in the polarity switching of the line periods, characterized in that the input of the counter is preceded by a switching stage for changing the signal which advances the counter in a specific line period, which stage receives the signal of line synchronizing frequency at one input and a pulse which appears depending on the transition from one track to the next track at a further input, which pulse initiates said change, a phse shift in accordance with the pattern of consecutive polarities being introduced in the control signal which is supplied to the polarity switching device by the decoding device.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |