US4862299A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clock signal regenerator
Assignee: Kenwood KK
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Filing: 1988-01-29
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Granted: 1989-08-29
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Expires: 2008-01-29
Abstract
Abstract In a clock signal regenerator of reproducing apparatus for reproducing a PCM converted signal recorded on magnetic recording medium through helical scan of a slant azimuth method, an output voltage from a loop filter in a PLL circuit which derives clock signals based on the PCM reproduced signals is switched in response to switching between magnetic heads having a different azimuth angle.
Inventors
- 👤 Hiroyuki Hagita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:42
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10527
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
172 words
Magnetic record/reproduction apparatus including a rotary drum provided with substantially opposed first and second magnetic heads, the first and second magnetic heads being respectively arranged with different azimuth angles for a guardband-less recording, the apparatus comprising: a phase-locked loop circuit in response to first and second reproduced signals respectively from said first and second magnetic heads for locking the transmission rates of the first and second reproduced signals to generate first and second reproduction clocks; means in response to a rotary phase signal from the rotary drum for generating a timing signal to change over the reproduction mode between the signals from said first and second magnetic heads; and means in response to said timing signal for applying to said phase-locked loop circuit a DC voltage level at the start point of the locking to the transmission rate of each of the first and second reproduced signals, the applied DC voltage level corresponding to a DC voltage level which the phase-locked loop circuit held from one rotation of the rotary drum earlier.
Claim 2
Dependent Claim
172 words
Magnetic record/reproduction apparatus including a rotary drum provided with substantially opposed first and second magnetic heads, the first and second magnetic heads being respectively arranged with different azimuth angles for a guardband-less recording, the apparatus comprising: a phase-locked loop circuit in response to first and second reproduced signals respectively from said first and second magnetic heads for locking the transmission rates of the first and second reproduced signals to generate first and second reproduction clocks; means in response to a rotary phase signal from the rotary drum for generating a timing signal to change over the reproduction mode between the signals from said first and second magnetic heads; and means in response to said timing signal for applying to said phase-locked loop circuit a DC voltage level at the start point of the locking to the transmission rate of each of the first and second reproduced signals, the applied DC voltage level corresponding to a DC voltage level which the phase-locked loop circuit held from one rotation of the rotary drum earlier.
Claim 3
Dependent Claim
40 words
Magnetic record/reproduction apparatus according to claim 1, wherein said phase-locked loop circuit includes first and second DC level holding capacitors, the first and second holding capacitors being alternately connected to the phase-locked loop circuit in response to the timing signal.
Claim 4
Dependent Claim
38 words
Magnetic record/reproduction apparatus according to claim 1, wherein said phase-locked loop circuit includes first and second lowpass filters, the first and second lowpass filters being alternately connected to the phase-locked loop circuit in response to the timing signal.
Claim 5
Dependent Claim
23 words
Magnetic recording/reproduction apparatus according to claim 1, wherein the reproduced signals from said first and second magnetic heads are in digital signal format.
References Cited (Backward Citations)
US4692914A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |