US4577241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital video tape recorder apparatus
Assignee: Sony Corp
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Filing: 1984-03-21
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Granted: 1986-03-18
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Expires: 2004-03-21
Abstract
Abstract Apparatus for regenerating a clock pulse signal from a stream of data derived from a variable-speed digital video tape recorder and lacking a strong clock pulse component, comprises a first phase-locked loop circuit to which the incoming data is supplied and which includes a loop filter of relatively wide bandwidth and a first voltage controlled oscillator. The first voltage controlled oscillator supplies a regenerated clock pulse signal to a second phase-locked loop circuit which includes a loop filter of relatively narrow bandwidth and a second voltage controlled oscillator which supplies a regenerated output clock pulse signal. The first and second voltage controlled oscillators are controlled by a preset control signal derived by a preset control signal generator arrangement in dependence on the direction and speed of a magnetic tape from which the video tape recorder is reproducing the stream of data.
Inventors
- 👤 James H. Wilkinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:16
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/93; H04N5/935
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
191 words
Digital video tape recorder apparatus comprising: means operative in reproduction modes of the apparatus to derive a stream of coded data reproduced from a magnetic tape, a speed-dependent pulse signal of frequency dependent on the transport speed of said tape, and a direction signal indicating the direction of transport of said tape; a first phase-locked loop circuit to which said stream of data is supplied and including a loop filter of relatively wide bandwidth and a first voltage controlled oscillator for producing a first regenerated clock pulse signal from said stream of data; a second phase-locked loop circuit to which said first regenerated clock pulse signal is supplied and including a loop filter of relatively narrow bandwidth and a second voltage controlled oscillator for producing an output regenerated clock pulse signal from said first regenerated clock pulse signal and for use in regenerating said stream of data; and a preset control signal generator means for deriving at least one preset control signal in dependence on said speed-dependent pulse signal and said direction signal and for supplying said at least one preset control signal to said first and second voltage controlled oscillators.
Claim 2
Dependent Claim
191 words
Digital video tape recorder apparatus comprising: means operative in reproduction modes of the apparatus to derive a stream of coded data reproduced from a magnetic tape, a speed-dependent pulse signal of frequency dependent on the transport speed of said tape, and a direction signal indicating the direction of transport of said tape; a first phase-locked loop circuit to which said stream of data is supplied and including a loop filter of relatively wide bandwidth and a first voltage controlled oscillator for producing a first regenerated clock pulse signal from said stream of data; a second phase-locked loop circuit to which said first regenerated clock pulse signal is supplied and including a loop filter of relatively narrow bandwidth and a second voltage controlled oscillator for producing an output regenerated clock pulse signal from said first regenerated clock pulse signal and for use in regenerating said stream of data; and a preset control signal generator means for deriving at least one preset control signal in dependence on said speed-dependent pulse signal and said direction signal and for supplying said at least one preset control signal to said first and second voltage controlled oscillators.
Claim 3
Dependent Claim
39 words
Apparatus according to claim 1 wherein said preset control signal generator means comprises a counter for deriving from said speed-dependent pulse signal a respective speed signal representing the distance travelled by said tape in respective successive intervals of time.
Claim 4
Dependent Claim
37 words
Apparatus according to claim 2 wherein said preset control signal generator arrangement further comprises a programmable read-only memory for deriving said at least one preset control signal in dependence on said speed signal and said direction signal.
Claim 5
Dependent Claim
23 words
Apparatus according to claim 1 wherein said first phase-locked loop circuit includes a phase detector to which said stream of data is supplied.
Claim 6
Dependent Claim
26 words
Apparatus according to claim 4 wherein said second phase-locked loop circuit includes a phase frequency detector to which said first regenerated clock pulse signal is supplied.
Claim 7
Dependent Claim
34 words
Apparatus according to claim 1 wherein said output regenerated clock pulse signal is supplied to a latch circuit to which said stream of data is also supplied, said latch circuit supplying output regenerated data.
References Cited (Backward Citations)
US3900890A
Cited
US4231071A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |