US4815061A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reproducing device for frequency modulated signals
Assignee: Canon Inc
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Filing: 1987-04-30
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Granted: 1989-03-21
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Expires: 2007-04-30
Abstract
Abstract A frequency modulated signal reproducing device includes a reproducing device for reproducing a frequency modulated signal from a recording medium; a pilot signal generating circuit for generating a pilot signal relative to a discontinued part of the signal reproduced by the reproducing device; a phase lock circuit which generates a phase locked signal which is phase locked relative to the reproduced signal; a demodulating circuit for frequency demodulating the phase locked signal; and a control circuit for controlling the response speed of the phase lock circuit 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
2026-10-29 21:10
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: 9
Claim 1
Independent Claim
112 words
A reproducing device for a frequency modulated signal, comprising: (a) reproducing means for reproducing a frequency modulated signal from a recording medium; (b) forming means for forming a signal variable in level in response to variation in frequency of the frequency modulated signal reproduced by said reproducing means; (c) generating means for generating a pilot signal relative to a discontinued part of the frequency modulated signal reproduced by said reproducing means; (d) removing means for removing a high frequency zone of the signal formed by said forming 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
112 words
A reproducing device for a frequency modulated signal, comprising: (a) reproducing means for reproducing a frequency modulated signal from a recording medium; (b) forming means for forming a signal variable in level in response to variation in frequency of the frequency modulated signal reproduced by said reproducing means; (c) generating means for generating a pilot signal relative to a discontinued part of the frequency modulated signal reproduced by said reproducing means; (d) removing means for removing a high frequency zone of the signal formed by said forming 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
26 words
A device according to claim 1, wherein said forming means includes frequency demodulating means for frequency demodulating the frequency modulated signal reproduced by said reproducing means.
Claim 4
Dependent Claim
51 words
A device according to claim 2, wherein said removing means includes a first low-pass filter and a second low-pass filter which is of a lower cut-off frequency then said first low-pass filter, said first and second low-pass filters being arranged to filter a signal generated by said frequency demodulating means, respectively.
Claim 5
Dependent Claim
35 words
A device according to claim 3, wherein said control means includes a switching circuit arranged to selectively produce a signal coming through said first low-pass filter, and a signal coming through said second low-pass filter.
Claim 6
Dependent Claim
67 words
A device according to claim 1, wherein said forming means includes a controllable oscillator, comparison means for phase-comparing a signal generated by said controllable oscillator with the frequency modulated signal reproduced by said reproducing means, and frequency demodulating means for frequency demodulating a signal generated by said controllable oscillator, said controllable oscillator having an oscillation frequency variable in response to a signal output by said comparison means.
Claim 7
Dependent Claim
56 words
A device according to claim 5, wherein said removing means includes a low-pass filter for filtering the signal output from said comparison means to supply said controllable oscillator, and said control means includes a time constant varying circuit which is arranged to vary the cut-off frequency of said low-pass filter in accordance with said pilot signal.
Claim 8
Dependent Claim
50 words
A device according to claim 5, wherein said removing means includes a first low-pass filter and a second low-pass filter which is of a lower cut-off frequency than said first low-pass filter, said first and second low-pass filters being arranged to filter the signal output by said comparison means, respectively.
Claim 9
Dependent Claim
38 words
A device according to claim 7, wherein said control means includes a switching circuit arranged to selectively supply a signal coming through said first low-pass filter and a signal coming through said second low-pass filter said controllable oscillator.
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) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |