US3594498A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color-phase-correcting circuitry with one-hundred eighty degree ambiguity elimination
Assignee: Central Dynamics Ltd
•
Filing: 1969-10-09
•
Granted: 1971-07-20
•
Expires: 1989-10-09
Abstract
Abstract Color-phase-correcting circuitry for use with a color video tape machine is disclosed. Such machines typically include (1) a tape drive, (2) means for controlling the speed of the tape which are responsive to the vertical synchronizing pulses derived from a video reference signal (3) a read/write head for reading a signal from the tape to thereby derive a composite color signal, (4) means for adjusting the phase of the composite signal so that the horizontal and vertical synchronizing pulses of the composite signal are in phase with the horizontal and vertical pulses of the video reference signal, and (5) means for adjusting the phase of the composite signal so that the color subcarrier of the composite signal will be in phase with the color subcarrier of the reference signal. This adjustment is made following the adjustment described in (4) and under some circumstances can cause the phase adjustment described in (4) to be destroyed. The improvement includes a sync signal comparator which compares the phase of the horizontal synchronizing pulses of the composite color signal with the phase of the horizontal synchronizing pulses of the video reference signal after the correction described in (5) has taken place. If any phase deviation exists, an appropriate signal is applied to circuitry which controls the tape speed to shift the video signal one picture frame. Phase synchronism is then obtained with respect to both the vertical and horizontal synchronizing pulses and with respect to the color subcarrier signals.
Inventors
- 👤 Peter W Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:14
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/873; G; G11; G11B; G11B27/00; G11B27/02; G11B27/022; G11B27/024
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
292 words
Color-phase-correcting circuitry for use with a tape machine including a tape, tape drive, servo means for controlling the speed of said tape in accordance with a control signal applied thereto, a read head for reading a composite color signal stored on said tape in response to relative movement between said tape and said read head, first sync comparator means for developing said control signal for said servo means whenever the horizontal and vertical synchronizing pulses of the said composite signal are not in phase with the horizontal and vertical pulses of a color reference signal and color-phase-adjusting means for adjusting the phase of said composite color signal so as to maintain the phase of the color subcarrier of the color reference signal whereby the phase adjustment made by said first phase adjusting means can be destroyed if a 180* phase difference existed between the color subcarriers of the composite color signal and the color reference signal at the time the phase adjustment was made by said first phase adjustment means, said color-phase-correcting circuitry comprising: second sync comparator means responsive to the output signal from said color-phase-adjusting means for comparing the phase of at least some of the synchronizing pulses of said composite color signal with the phase of at least some of the synchronizing pulses of said color reference signal and for providing an output signal whenever a deviation exists therebetween; and frame-shifting means responsive to the output signal from said sync comparator means for shifting the color reference signal one frame to thereby shift the composite color signal so that its synchronizing pulses and the color subcarrier are in phase synchronism with the synchronizing pulses and the color subcarrier of said color reference signal if the said 180* phase difference existed.
Claim 2
Dependent Claim
292 words
Color-phase-correcting circuitry for use with a tape machine including a tape, tape drive, servo means for controlling the speed of said tape in accordance with a control signal applied thereto, a read head for reading a composite color signal stored on said tape in response to relative movement between said tape and said read head, first sync comparator means for developing said control signal for said servo means whenever the horizontal and vertical synchronizing pulses of the said composite signal are not in phase with the horizontal and vertical pulses of a color reference signal and color-phase-adjusting means for adjusting the phase of said composite color signal so as to maintain the phase of the color subcarrier of the color reference signal whereby the phase adjustment made by said first phase adjusting means can be destroyed if a 180* phase difference existed between the color subcarriers of the composite color signal and the color reference signal at the time the phase adjustment was made by said first phase adjustment means, said color-phase-correcting circuitry comprising: second sync comparator means responsive to the output signal from said color-phase-adjusting means for comparing the phase of at least some of the synchronizing pulses of said composite color signal with the phase of at least some of the synchronizing pulses of said color reference signal and for providing an output signal whenever a deviation exists therebetween; and frame-shifting means responsive to the output signal from said sync comparator means for shifting the color reference signal one frame to thereby shift the composite color signal so that its synchronizing pulses and the color subcarrier are in phase synchronism with the synchronizing pulses and the color subcarrier of said color reference signal if the said 180* phase difference existed.
Claim 3
Dependent Claim
43 words
Circuitry as in claim 1 where frame-shifting means increases the repetition frequency of said vertIcal synchronizing pulses and where said means for controlling the speed of said tape controls the speed in accordance with the repetition frequency of the said vertical synchronizing pulses.
Claim 4
Dependent Claim
27 words
Circuitry as in claim 2 where said frame-shifting means increases the frequency of said vertical synchronizing pulses by subtracting line pulses from the said color reference signal.
Claim 5
Dependent Claim
68 words
Circuitry as in claim 3 where said frame shifting means causes said tape to be shifted one frame if, after the horizontal synchronizing pulses of the composite color signal and the color reference signal are initially phase synchronized by said first sync comparator means, said second sync comparator means detects a phase deviation between the respective synchronizing pulses of the composite color signal and the color reference signal.
Claim 6
Dependent Claim
321 words
Color-phase-correcting circuitry for use with a tape machine including a tape, tape drive, servo means for controlling the speed of said tape in accordance with the repetition rate of the vertical synchronizing pulses of a reference signal applied thereto, a read head for reading a composite color signal stored on said tape in response to relative movement between said tape and said read head, first sync comparator means for developing said control signal for said servo means whenever the horizontal and vertical synchronizing pulses of the said composite signal are not in phase with the horizontal and vertical pulses of a color reference signal and color-phase-adjusting means for adjusting the phase of said composite color video signal so as to maintain the phase of the color subcarrier of the color reference signal whereby the phase adjustment made by said first phase-adjusting means can be destroyed if a 180* phase difference existed between the color subcarriers of the composite color signal and the color reference at the time the phase adjustment was made by said first phase adjustment means, said color phase-correcting circuitry comprising: second sync comparator means responsive to the output signal from said color phase adjustment means for comparing the phase of the horizontal synchronizing pulses of said composite color video signal with the phase of the horizontal synchronizing pulses of said reference signal and for providing an output signal whenever a deviation exists therebetween; and means responsive to the output signal from said sync comparator means and to the vertical synchronizing pulses of said video reference signal for increasing the repetition rate of the vertical synchronizing pulses applied to said first comparator means; whereby, if said 180* phase difference existed, said tape has the speed thereof adjusted until the synchronizing pulses and the color subcarrier of said composite color video signal are respectively in phase synchronism with the synchronizing pulses and the color subcarrier of said video reference signal.
Claim 7
Dependent Claim
321 words
Color-phase-correcting circuitry for use with a tape machine including a tape, tape drive, servo means for controlling the speed of said tape in accordance with the repetition rate of the vertical synchronizing pulses of a reference signal applied thereto, a read head for reading a composite color signal stored on said tape in response to relative movement between said tape and said read head, first sync comparator means for developing said control signal for said servo means whenever the horizontal and vertical synchronizing pulses of the said composite signal are not in phase with the horizontal and vertical pulses of a color reference signal and color-phase-adjusting means for adjusting the phase of said composite color video signal so as to maintain the phase of the color subcarrier of the color reference signal whereby the phase adjustment made by said first phase-adjusting means can be destroyed if a 180* phase difference existed between the color subcarriers of the composite color signal and the color reference at the time the phase adjustment was made by said first phase adjustment means, said color phase-correcting circuitry comprising: second sync comparator means responsive to the output signal from said color phase adjustment means for comparing the phase of the horizontal synchronizing pulses of said composite color video signal with the phase of the horizontal synchronizing pulses of said reference signal and for providing an output signal whenever a deviation exists therebetween; and means responsive to the output signal from said sync comparator means and to the vertical synchronizing pulses of said video reference signal for increasing the repetition rate of the vertical synchronizing pulses applied to said first comparator means; whereby, if said 180* phase difference existed, said tape has the speed thereof adjusted until the synchronizing pulses and the color subcarrier of said composite color video signal are respectively in phase synchronism with the synchronizing pulses and the color subcarrier of said video reference signal.
References Cited (Backward Citations)
US3474190A
Cited
US3461226A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |