US3573359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video tape apparatus having sync signal control dropout compensation
Assignee: Ampex Corp
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Filing: 1968-05-06
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Granted: 1971-04-06
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Expires: 1988-05-06
Abstract
Abstract A recorded composite video signal having periodic dropout intervals is processed by a system which provides an indication of the position and duration of such dropout intervals and maintains the output signal at a fixed level during these intervals. Circuitry may be provided for inserting horizontal synchronizing pluses during each dropout interval. A system is also disclosed which detects the dropout intervals, and is employed in the above processing system as well as in a system for maintaining the stretch of the recording tape-medium constant by deriving a signal indication thereof from comparison of the horizontal synchronizing pulses before and after each dropout interval. A tension-controlling mechanism is responsive to the signal, and applies suitable tension on the tape.
Inventors
- 👤 Barrett Earl Guisinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:44
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/88; H04N9/882; H04N5/00; H04N5/76; H04N5/91; H04N5/93; H04N5/932
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
246 words
A video processing system for use in the reproducing circuit of a video tape-reproducing apparatus which supplies a composite video signal having periodic signal dropout intervals to the input of the system, comprising main circuit means responsive to the video signal for providing a main signal path for said system, including output terminal means for deriving a processed signal control circuit means also responsive to the same video signal for providing a signal control path for said system; said control circuit means including dropout signal means for providing a signal indicative of the position and duration of the dropout interval of the video signal, said control circuit means including synchronizing pulse stripping means responsive to the video signal and having means for providing only vertical input synchronizing pulses to said dropout signal means, said dropout signal means comprising delay means responsive to the output of said synchronizing pulse stripping means for providing a signal at a predetermined time after each vertical synchronizing pulse, and dropout position means responsive to said signal to derive a pulse indicative of the position of the dropout interval with respect to the previous vertical synchronizing pulse; said main circuit means comprising controllable means in the main signal path responsive to the signal provided by said dropout signal means for providing a video output which is fixed at a predetermined level for the period of the dropout interval but otherwise permits the video signal to pass therethrough to the output terminal means.
Claim 2
Dependent Claim
246 words
A video processing system for use in the reproducing circuit of a video tape-reproducing apparatus which supplies a composite video signal having periodic signal dropout intervals to the input of the system, comprising main circuit means responsive to the video signal for providing a main signal path for said system, including output terminal means for deriving a processed signal control circuit means also responsive to the same video signal for providing a signal control path for said system; said control circuit means including dropout signal means for providing a signal indicative of the position and duration of the dropout interval of the video signal, said control circuit means including synchronizing pulse stripping means responsive to the video signal and having means for providing only vertical input synchronizing pulses to said dropout signal means, said dropout signal means comprising delay means responsive to the output of said synchronizing pulse stripping means for providing a signal at a predetermined time after each vertical synchronizing pulse, and dropout position means responsive to said signal to derive a pulse indicative of the position of the dropout interval with respect to the previous vertical synchronizing pulse; said main circuit means comprising controllable means in the main signal path responsive to the signal provided by said dropout signal means for providing a video output which is fixed at a predetermined level for the period of the dropout interval but otherwise permits the video signal to pass therethrough to the output terminal means.
Claim 3
Dependent Claim
68 words
The system of claim 1 wherein said synchronizing-pulse stripping means comprises means for providing the horizontal synchronizing pulses from the input signal, and wherein said main circuit means comprises a gated clamping means in the main signal path adapted to receive the input video signal and responsive to the horizontal synchronizing pulses from said stripping means for clamping the backporch portions of the signal to a fixed level.
Claim 4
Dependent Claim
44 words
The system of claim 1 wherein said dropout signal means further comprises pulse width determining means responsive to the dropout position means for providing a pulse to said controllable means in the main signal path having a duration approximately coextensive with the dropout interval.
Claim 5
Dependent Claim
77 words
The system of claim 1 wherein said dropout signal means comprises pulse width determining means responsive to the pulse derived by said dropout position means for providing a pulse output having a pulse width approximately coextensive with the dropout interval, and wherein said control circuit means comprises pulse inserting means responsive to the signal provided by said dropout signal means for inserting horizontal synchronizing pulses in the signal of the main circuit means during the dropout interval.
Claim 6
Dependent Claim
56 words
The system of claim 4 further comprising an inhibit gate connected in said control circuit path between the input and said vertical synchronizing-pulse stripping means and responsive to the output of said pulse width determining means for blocking said control circuit means during the dropout interval, whereby noise signals are prevented from passing through the system.
Claim 7
Dependent Claim
34 words
The system of claim 4 comprising second delay means responsive to the output of said vertical delay means for controlling the reinsertion of vertical synchronizing signals into the signal of the main circuit means.
Claim 8
Dependent Claim
36 words
The system of claim 4 wherein the output pulse of the pulse width determining means is slightly greater than the dropout interval and extends from a time just prior to a time just after said interval.
Claim 9
Dependent Claim
65 words
The system of claim 1 wherein said pulse-inserting means comprises controlled oscillator means providing properly phAsed pulses at the horizontal synchronizing rate, and logic means responsive to said controlled oscillator means and to said pulse width determining means for providing pulses at the horizontal synchronizing rate only during the dropout interval, and means for adding said pulses to the signal of the main circuit means.
Claim 10
Dependent Claim
47 words
The system of claim 8 wherein said logic means comprises an AND gate, said pulse-inserting means further comprising an OR gate having one input coupled to the output of the AND gate and another input coupled to a source of stripped synchronizing pulses from the input signal.
Claim 11
Dependent Claim
40 words
The system of claim 4 wherein said controllable means comprises clamping means responsive to the pulse output of said pulse width determining means for clamping the signal of the main signal means to said predetermined level during each dropout interval.
Claim 12
Dependent Claim
66 words
The system of claim 10 further comprising clipping means coupled to the output of said clamping means for removing all portions of the video signal of a lower level than the black level, means for generating vertical synchronizing pulses and horizontal synchronizing pulses in synchronism with the original composite synchronizing pulses, and means for adding the generated synchronizing pulses to the output of said clipping means.
Claim 13
Dependent Claim
38 words
The system of claim 11 further comprising chroma separator means coupled between said clamping means and said clipping means, and means for shunting the chroma portions of the video signal around the clipping means to said adding means.
Claim 14
Dependent Claim
90 words
The system of claim 4 wherein said synchronizing-pulse stripping means comprises further means for providing the horizontal synchronizing pulses from the input signal, the system further comprising gating-pulse generator means responsive to the horizontal synchronizing pulses for producing gating pulses at the horizontal synchronizing rate having a pulse width slightly greater than the horizontal synchronizing pulses, controllable stripping means responsive to the signal of the main signal means and to said gating pulses for providing a synchronizing pulse output substantially free of undesirable components normally adjacent the stripped synchronizing pulses.
Claim 15
Dependent Claim
49 words
The system of claim 13 further comprising logic means responsive to the output of said controllable stripping means and said pulse inserting means to provide synchronizing pulses during the dropout interval as well as otherwise, and means for adding said pulses to the signal of the main circuit means.
Claim 16
Dependent Claim
13 words
The system of claim 14 wherein said logic means comprises an OR gate.
Claim 17
Independent Claim
299 words
A system for controlling the tension of a magnetic tape in a video tape recorder, said tape having thereon a carrier modulated by a composite video signal which modulated carrier has a dropout interval in each video field, said video tape recorder having means therein to demodulate said modulated carrier to supply the composite video signal with the dropout interval to the input to said system, said system comprising a controlled oscillator for generating output pulses at a normal horizontal synchronizing pulse rate; circuit means responsive to the composite video signal for producing an output indicative of the horizontal synchronizing pulses in said video signal and the absence of such pulses during the dropout interval; comparison means responsive to the horizontal synchronizing pulses from said circuit means and to the output of said controlled oscillator for producing an error signal indicative of the phase difference therebetween; means coupling the error signal to said controlled oscillator for slowly altering the output thereof to reduce the error signal from said comparing means to a predetermined value; said oscillator maintaining its output during the dropout essentially as it was just prior to the dropout so that the error signal is indicative of the phase change between the horizontal synchronizing pulses of the video signal just prior to the dropout interval and just after the dropout iNterval, to thereby provide an indication of changes in the tape tension; dropout detecting means responsive to the absence and then presence of horizontal synchronizing pulses for producing an output indicative of the termination of the dropout interval, and means responsive to said detecting means output for sampling the error signal at a predetermined time after the termination of the dropout interval; and control means responsive to the sampled error signal for maintaining the tape tension constant.
Claim 18
Independent Claim
299 words
A system for controlling the tension of a magnetic tape in a video tape recorder, said tape having thereon a carrier modulated by a composite video signal which modulated carrier has a dropout interval in each video field, said video tape recorder having means therein to demodulate said modulated carrier to supply the composite video signal with the dropout interval to the input to said system, said system comprising a controlled oscillator for generating output pulses at a normal horizontal synchronizing pulse rate; circuit means responsive to the composite video signal for producing an output indicative of the horizontal synchronizing pulses in said video signal and the absence of such pulses during the dropout interval; comparison means responsive to the horizontal synchronizing pulses from said circuit means and to the output of said controlled oscillator for producing an error signal indicative of the phase difference therebetween; means coupling the error signal to said controlled oscillator for slowly altering the output thereof to reduce the error signal from said comparing means to a predetermined value; said oscillator maintaining its output during the dropout essentially as it was just prior to the dropout so that the error signal is indicative of the phase change between the horizontal synchronizing pulses of the video signal just prior to the dropout interval and just after the dropout iNterval, to thereby provide an indication of changes in the tape tension; dropout detecting means responsive to the absence and then presence of horizontal synchronizing pulses for producing an output indicative of the termination of the dropout interval, and means responsive to said detecting means output for sampling the error signal at a predetermined time after the termination of the dropout interval; and control means responsive to the sampled error signal for maintaining the tape tension constant.
Claim 19
Dependent Claim
52 words
Video magnetic tape apparatus comprising the system according to claim 16 including a supply reel for supplying the magnetic tape to a takeup reel, said control means including a variable brake on said supply reel responsive to the error signal for applying tension of said tape to maintain a constant tape stretch.
Claim 20
Dependent Claim
57 words
The system of claim 16 further comprising inhibiting means for opening and closing the circuit path for the output of said circuit means to said comparing means, and means coupling the output of said detecting means to said inhibiting means to open said circuit path to said comparing means just before and into the subsequent dropout interval.
Claim 21
Dependent Claim
55 words
The system of claim 18 wherein the means responsive to the dropout-detecting means output comprises delay means for generating an output signal approximately one field after receiving its input signal, and inhibit means responsive to the delay means output for preventing said dropout-detecting means from producing a new output signal until the succeeding dropout interval.
Claim 22
Dependent Claim
28 words
The system of claim 16 wherein said circuit means includes stripping means responsive to the composite video signal for providing an output of only the composite synchronizing signal.
Claim 23
Dependent Claim
40 words
The system of claim 20 wherein said circuit means further includes inhibiting means in the signal path responsive to said controllable oscillator output for gating only the horizontal synchronizing pulses through the circuit to prevent the passage of noise therethrough.
Claim 24
Dependent Claim
110 words
The system of claim 21 wherein said circuit means further includes a pulse generator responsive to the output of said inhibiting means for producing pulses corresponding to the horizontal synchronizing signal, said system further comprising second inhibiting means in the circuit path from said pulse generator to said comparing means, dropout-detecting means also coupled to said pulse generator and responsive to the absence of horizontal synchronizing pulses for producing an output indicative of the termination of the dropout interval, means responsive to said detecting means output and coupled to said second inhibiting means for opening said circuit path to the comparing means just before and into the subsequent dropout interval.
Claim 25
Dependent Claim
47 words
The system of claim 22 further comprising sampling means also responsive to said dropout-deleting means output for sampling the error signal at a predetermined time after the termination of the dropout interval, and means responsive to the sampled error signal for varying the tension on said tape.
Claim 26
Dependent Claim
198 words
A video processing system for use in the reproducing circuit of a video tape-reproducing apparatus which supplies a composite video signal having periodic signal dropout intervals to the input of the system comprising main circuit means responsive to the video signal for providing a main signal path for said system, including output terminal means for deriving a processed signal; control circuit means also responsive to the same video signal for providing a signal control path for said system; said control circuit means including dropout signal means for providing a signal indicative of the position and duration of the dropout interval in the video signal; said main circuit means comprising controllable means in the main signal path responsive to the signal provided by said dropout signal means for providing a video output which is fixed at a predetermined level for the period of the dropout interval but otherwise permits the video signal To pass therethrough to the output terminal means, said dropout signal means including means responsive to the absence of horizontal synchronizing signals in the video signal for a period greater than a predetermined time for providing an output signal indicative of the position of each dropout interval.
Claim 27
Dependent Claim
198 words
A video processing system for use in the reproducing circuit of a video tape-reproducing apparatus which supplies a composite video signal having periodic signal dropout intervals to the input of the system comprising main circuit means responsive to the video signal for providing a main signal path for said system, including output terminal means for deriving a processed signal; control circuit means also responsive to the same video signal for providing a signal control path for said system; said control circuit means including dropout signal means for providing a signal indicative of the position and duration of the dropout interval in the video signal; said main circuit means comprising controllable means in the main signal path responsive to the signal provided by said dropout signal means for providing a video output which is fixed at a predetermined level for the period of the dropout interval but otherwise permits the video signal To pass therethrough to the output terminal means, said dropout signal means including means responsive to the absence of horizontal synchronizing signals in the video signal for a period greater than a predetermined time for providing an output signal indicative of the position of each dropout interval.
Claim 28
Dependent Claim
74 words
The system of claim 24 wherein said dropout signal means further includes delay means responsive to said indicating output signal for providing a delayed output at a time just prior to the occurrence of the next successive dropout interval and pulse-generating means for providing a clamping signal to said controllable means in the main signal path so that the video output is fixed at a predetermined level for the period of the dropout interval.
Claim 29
Dependent Claim
35 words
The system of claim 25 wherein said control circuit means comprises pulse-inserting means responsive to said clamping signal for inserting horizontal synchronizing pulses in the signal of the main circuit means during the dropout interval.
Claim 30
Dependent Claim
45 words
The system of claim 25 wherein said control circuit means includes a normally open controllable gating means serially connected in the control circuit path and means responsive to said clamping signal from said pulse generating means for closing said gating means during each dropout interval.
Claim 31
Dependent Claim
31 words
The system of claim 25 wherein said delay means is coupled to said means responsive to the absence of horizontal synchronizing signals to inhibit the same during the period of delay.
Claim 32
Independent Claim
89 words
A system for detecting periodic dropout intervals in the reproduction of a modulated composite video signal from a magnetic record medium having such periodic dropout intervals, comprising first means responsive to the composite video signal for providing pulses indicative of the horizontal synchronizing signals thereon, and second means coupled to said first means and responsive to said horizontal pulses for providing an output signal indicating the position of a dropout interval in the event of an absence of such horizontal pulses for a period greater than a predetermined time.
Claim 33
Independent Claim
89 words
A system for detecting periodic dropout intervals in the reproduction of a modulated composite video signal from a magnetic record medium having such periodic dropout intervals, comprising first means responsive to the composite video signal for providing pulses indicative of the horizontal synchronizing signals thereon, and second means coupled to said first means and responsive to said horizontal pulses for providing an output signal indicating the position of a dropout interval in the event of an absence of such horizontal pulses for a period greater than a predetermined time.
Claim 34
Dependent Claim
35 words
The system of claim 29 wherein said second means comprises delay means responsive to the position-indicating signal for providing an output at a time just prior to the occurrence of the next periodic dropout interval.
Claim 35
Dependent Claim
72 words
The system of claim 29 wherein said second means comprises a gated integrator circuit having an output which slowly deviates from a reference value in the absence of horizontal pulses thereto and is abruptly restored to its reference value upon the reoccurrence of said horizontal pulses and a differentiating circuit coupled to the output of said gated integrator circuit for providing an output pulse indicative of the termination of a dropout interval.
Claim 36
Dependent Claim
74 words
The system of claim 31 wherein said second means further comprises a monostable multivibrator responsive to the output of said differentiating circuit for providing a pulse extending from the termination of said dropout interval to a time just prior to the occurrence of the next successive dropout interval, and means coupling an output of said multivibrator to said gated integrator circuit for inhibiting the operation of said gated integrator circuit during the pulse period.
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) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |