US4692914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reproducing device for frequency modulated signals
Assignee: Canon Inc
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Filing: 1984-05-31
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Granted: 1987-09-08
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Expires: 2004-05-31
Abstract
Abstract A frequency modulated signal reproducing device comprises a reproducing device for reproducing a frequency modulated signal from a recording medium; a pilot signal generating device for generating a pilot signal relative to a discontinued part of the signal reproduced by the reproducing means; a phase lock device which generates a phase locked signal which is phase locked relative to the reproduced signal; a demodulating device for frequency demodulating the phase locked signal; and control means for controlling the response speed of the phase lock means on the basis of the pilot signal.
Inventors
- 👤 Hiroto Yasumura
- 👤 Susumu Kozuki
- 👤 Masahiro Takei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:26
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/02; G11B20/06; G11B20/10; G11B20/18; G11B20/24; H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/802
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
A reproducing device for a frequency modulated signal, comprising: (a) reproducing means for reproducing a frequency modulated signal from a recording medium; (b) demodulating means for frequency demodulating a signal reproduced by said reproducing means; (c) generating means for generating a pilot signal relative to a discontinued part of the signal reproduced by said reproducing means; (d) removing means for removing a high frequency zone of a signal produced from said demodulating means; and (e) control means for controlling in accordance with said pilot signal the frequency zone which is to be removed by said removing means.
Claim 2
Dependent Claim
97 words
A reproducing device for a frequency modulated signal, comprising: (a) reproducing means for reproducing a frequency modulated signal from a recording medium; (b) demodulating means for frequency demodulating a signal reproduced by said reproducing means; (c) generating means for generating a pilot signal relative to a discontinued part of the signal reproduced by said reproducing means; (d) removing means for removing a high frequency zone of a signal produced from said demodulating means; and (e) control means for controlling in accordance with said pilot signal the frequency zone which is to be removed by said removing means.
Claim 3
Dependent Claim
31 words
A device according to claim 1, wherein said removing means includes a first low-pass filter and a second low-pass filter which has a lower cut-off frequency than said first low-pass filter.
Claim 4
Dependent Claim
42 words
A device according to claim 2, wherein said control means includes at least a switching circuit arranged to selectively produce a first demodulated signal coming through said second low pass filter and a second demodulated signal coming through said first low-pass filter.
Claim 5
Dependent Claim
27 words
A device according to claim 3, wherein said control means further includes a compensating circuit which compensates for time difference between said first and second demodulated signals.
Claim 6
Dependent Claim
14 words
A device according to claim 4, wherein said compensating circuit includes a delay circuit.
Claim 7
Dependent Claim
23 words
A device according to claim 1, wherein said generating means includes a drop-out detection circuit which detects a drop-out in said reproduced signal.
Claim 8
Dependent Claim
16 words
A device according to claim 6, wherein said reproducing means includes a plurality of reproducing heads.
Claim 9
Dependent Claim
30 words
A device according to claim 7, wherein said reproducing means includes a switching circuit which selectively makes output signal of said plurality of reproducing heads produced as said reproduced signal.
Claim 10
Dependent Claim
30 words
A device according to claim 8, wherein said generating means further includes a timing signal generating circuit which produces a signal according to the switching timing of said switching circuit.
Claim 11
Dependent Claim
42 words
A device according to claim 9, wherein said generating means further includes an OR circuit which is arranged to take a logical sum of a signal produced from said drop-out detection circuit and the signal produced from said timing signal generating circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-09-07 | 1991-03-09 | 1991-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-07 | 1995-03-09 | 1995-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-07 | 1999-03-09 | 1999-09-08 | $7700.00 | Window Closed / Lapsed |