Patent EP0398254B1 successfully refreshed from Google Patents.
EP0398254B1
Expired / Lapsed
EP
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FM demodulator
Assignee: Sanyo Electric Co Ltd
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Filing: 1990-05-15
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Granted: 1996-04-10
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Expires: 2010-05-15
Abstract
No abstract record available.
Inventors
- 👤 Katsunori Miura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 21:58
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/24; H03D3/241; H03D3/244; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/82; H04N9/83; H04N9/835; H04N9/8355
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
137 words
An FM demodulator for demodulating a predetermined band component of an FM signal comprising: variable gain amplifier means (5) receiving said FM signal for varying its gain in response to a control signal, filter means (6) comprising an active filter for passing a predetermined band component of a signal of said variable gain amplifier means (5), phase locked loop means including voltage controlled oscillator means (10) for FM demodulating the output signal of said filter means (6), and synchronous detection means (12) responsive to the output signal of said voltage controlled oscillator means (10) for synchronous detecting the output signal of said filter means (6) to supply the detected signal as said control signal to said variable gain amplifier means (5) so that the amplitude of said predetermined band component of said FM signal may be constant.
Claim 2
Dependent Claim
84 words
The FM demodulator according to claim 1, wherein said phase locked loop means (7) further comprises phase comparing means (8) for comparing the phase of the output signal of said filter means (6) with the phase of the output signal of said voltage controlled oscillator means (10) to output a signal having a voltage corresponding to the phase difference, said voltage controlled oscillator means (10) provides the signal with the corresponding frequency in response to the output signal of said phase comparing means (8).
Claim 3
Dependent Claim
54 words
The FM demodulator according to claim 2, wherein said phase locked loop means (7) further comprises a first low pass filter means (9) provided between said phase comparing means (8) and said voltage controlled oscillator means (10) for passing a predetermined low frequency component of the output signal of said phase comparing means (8).
Claim 4
Dependent Claim
47 words
The FM demodulator according to claim 3, further comprising: a second low pass filter means (13) provided between said synchronous detection means (12) and said variable gain amplifier means (5) for passing a predetermined low frequency component of the output signal of said synchronous detection means (12).
Claim 5
Dependent Claim
34 words
The FM demodulator according to claim 1, further comprising: phase shifting means (11) for phase shifting the output signal of said filter means (6) and providing the same to said synchronous detection means (12).
Claim 6
Dependent Claim
46 words
The FM demodulator according to claim 4, further comprising: muting means (15) for providing the output signal of said first low pass filter means (9) when the level of the output signal of said second low pass filter means (13) is higher than a predetermined level.
Claim 7
Dependent Claim
55 words
The FM demodulator according to claim 6, further comprising comparing means (16) for comparing the level of the output signal of said second low pass filter means (13) with a predetermined level to provide the compared result, and wherein said muting means (15) operates in response to the output signal of said comparing means (16).
References Cited (Backward Citations)
No citation records indexed.
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