US4361856A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video tape recorder
Assignee: Panasonic Holdings Corp
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Filing: 1980-12-05
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Granted: 1982-11-30
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Expires: 2000-12-05
Abstract
Abstract A video tape recorder of the helical scan type including two rotational video heads which have their phase and speed controlled. The video heads are mechanically displaced by 180° from each other and reproduce the video signal on the magnetic tape. The position of one of the video heads is indicated by PG pulse from a first pulse generator. A second pulse generator provides 2N pulses per revolution of the video heads, where N is an integer. A first divider is reset by the PG pulse, and divides by N the output pulse frequency of the second pulse generator, and adjusts the output phase of the first divider whose phase corresponds to the phase of the video heads. The second divider is also reset by each PG pulse and divides the output pulse frequency of the first divider by 2. Video signals reproduced by the video heads are chosen in accordance with the level of the output pulse from the second divider.
Inventors
- 👤 Hiroshi Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:59
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/18; G11B15/1808; G11B15/02; G11B15/12; G11B15/14; G11B15/46; G11B15/467; G11B15/473; G11B15/4731
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
176 words
A video tape recorder comprising two video heads which are mechanically displaced by 180° for reproducing recorded video signals on a magnetic tape, comprising: a first pulse generator means for providing a PG pulse for indicating the position of one of said video heads; a second pulse generator means for providing 2 N pulses per revolution of said video heads, wherein N is an integer; a driving means for driving said video heads; a phase controller means for controlling the phase of said video heads in accordance with a reference phase signal; a first divider means, reset by said PG pulse, for dividing an output frequency from said second pulse generator means by N and for generating output pulses having phases corresponding to the phases of said video heads; a second divider means for dividing an output frequency of said first divider means by 2; and a head switching means for choosing reproduced video signals by said video heads according to an output of said second divider means, and for sequentially outputting the chosen video signals.
Claim 2
Dependent Claim
176 words
A video tape recorder comprising two video heads which are mechanically displaced by 180° for reproducing recorded video signals on a magnetic tape, comprising: a first pulse generator means for providing a PG pulse for indicating the position of one of said video heads; a second pulse generator means for providing 2 N pulses per revolution of said video heads, wherein N is an integer; a driving means for driving said video heads; a phase controller means for controlling the phase of said video heads in accordance with a reference phase signal; a first divider means, reset by said PG pulse, for dividing an output frequency from said second pulse generator means by N and for generating output pulses having phases corresponding to the phases of said video heads; a second divider means for dividing an output frequency of said first divider means by 2; and a head switching means for choosing reproduced video signals by said video heads according to an output of said second divider means, and for sequentially outputting the chosen video signals.
Claim 3
Dependent Claim
99 words
A video tape recorder according to claim 1, wherein said phase controller means comprises: a phase detector means for detecting the phase of one of said video heads with respect to said reference phase signal; a speed discriminator for providing a speed signal according to an output signal of said second pulse generator means; an adder means for mixing the output signal of said phase detector means and an output signal of said speed discriminator; and a torque controller means for adjusting, according to an output signal of said adder means, the rotational torque for rotating said video heads.
Claim 4
Dependent Claim
42 words
A video tape recorder according to claim 1, wherein said driving means is a brushless DC motor which generates position signals to commutate its armature currents, said 2 N pulses being generated from these position signals by said second pulse generator means.
References Cited (Backward Citations)
US3580992A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-29 | 1986-05-31 | 1986-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-29 | 1990-05-31 | 1990-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-29 | 1994-05-31 | 1994-11-30 | $7700.00 | Window Closed / Lapsed |