US4112371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Muting and tuning indicator system for an FM receiver
Assignee: Nippon Gakki Co Ltd
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Filing: 1976-08-31
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Granted: 1978-09-05
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Expires: 1996-08-31
Abstract
Abstract In an FM receiver, the noise component is extracted from the output of the FM detector of the receiver, and the extracted noise component is rectified by a rectifier circuit. The output of this rectifier circuit serves as a driving signal for the tuning indicator or the muting circuit of the receiver.
Inventors
- 👤 Minoru Ogita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:45
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/344; H03J; H03J3/00; H03J3/02; H03J3/12; H03J3/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
143 words
A system adapted for use in a tuned FM receiver in order to control at least one of the functions of muting audio output from the receiver and providing an indication of the state of tuning of the receiver, said system comprising: means for demodulating a received signal; means for extracting noise components from the demodulated signal; an automatic gain control amplifier joined to said extracting means for receiving and amplifying the noise components; a rectifier connected to said amplifier for rectifying amplified noise components and delivering a dc signal which changes in accordance with variations in the level of said noise components; means for directing said dc signal to the amplifier for biasing thereof to produce a controlling signal at an output of said amplifier; and means operatively joined to the amplifier and responsive to the controlling signal for performing said function.
Claim 2
Independent Claim
143 words
A system adapted for use in a tuned FM receiver in order to control at least one of the functions of muting audio output from the receiver and providing an indication of the state of tuning of the receiver, said system comprising: means for demodulating a received signal; means for extracting noise components from the demodulated signal; an automatic gain control amplifier joined to said extracting means for receiving and amplifying the noise components; a rectifier connected to said amplifier for rectifying amplified noise components and delivering a dc signal which changes in accordance with variations in the level of said noise components; means for directing said dc signal to the amplifier for biasing thereof to produce a controlling signal at an output of said amplifier; and means operatively joined to the amplifier and responsive to the controlling signal for performing said function.
Claim 3
Dependent Claim
26 words
A system according to claim 1, in which said noise extracting means includes a high pass filter for allowing only high frequency noise components to pass.
Claim 4
Dependent Claim
29 words
A system according to claim 1 for providing a tuning indication function, wherein said means responsive to the controlling signal is a tuning indicator driven by said controlling signal.
Claim 5
Dependent Claim
44 words
A system according to claim 1 for providing a muting function, wherein said means responsive to the controlling signal is a muting circuit connected to an audio signal transmitting line of the receiver and driven by said controlling signal to mute the audio signal.
Claim 6
Independent Claim
176 words
A system adapted for use in a tuned FM receiver in order to control at least one of the functions of muting audio output from the receiver and providing an indication of the state of tuning of the receiver, said system comprising: means for demodulating a received signal; means for extracting noise components from the demodulated signal, said noise-extracting means including a high pass filter for allowing only high frequency noise components to pass; an automatic gain control amplifier joined to said extracting means for receiving and amplifying the noise components passed by said filter, said amplifier having a first output terminal grounded through a capacitive element; a rectifier connected to said amplifier for rectifying amplified noise components and delivering a dc voltage which changes in accordance with variations in the level of said noise components; means for directing said dc voltage to the amplifier for biasing thereof to produce a controlling signal at an output of said amplifier; and means operatively joined to the amplifier and responsive to the controlling signal for performing said function.
Claim 7
Independent Claim
176 words
A system adapted for use in a tuned FM receiver in order to control at least one of the functions of muting audio output from the receiver and providing an indication of the state of tuning of the receiver, said system comprising: means for demodulating a received signal; means for extracting noise components from the demodulated signal, said noise-extracting means including a high pass filter for allowing only high frequency noise components to pass; an automatic gain control amplifier joined to said extracting means for receiving and amplifying the noise components passed by said filter, said amplifier having a first output terminal grounded through a capacitive element; a rectifier connected to said amplifier for rectifying amplified noise components and delivering a dc voltage which changes in accordance with variations in the level of said noise components; means for directing said dc voltage to the amplifier for biasing thereof to produce a controlling signal at an output of said amplifier; and means operatively joined to the amplifier and responsive to the controlling signal for performing said function.
Claim 8
Dependent Claim
32 words
A system according to claim 5 for providing a tuning indication function, wherein said means responsive to the controlling signal is a tuning indicator connected between said first output terminal and ground.
Claim 9
Dependent Claim
31 words
A system according to claim 5, in which said amplifier is provided with a second output terminal in a current path which includes an impedance, the amplifier and said capacitive element.
Claim 10
Dependent Claim
44 words
A system according to claim 7 for providing a muting function, wherein said means responsive to the controlling signal is a muting circuit connected to an audio signal transmitting line of the receiver and having a gate means joined to the second output terminal.
Claim 11
Dependent Claim
38 words
A system according to claim 8, in which said gate means is a transistor having a base connected to the second output terminal and a collector-emitter connected between a point in said audio signal transmitting line and ground.
Claim 12
Dependent Claim
21 words
A system according to claim 9, said system further comprising a tuning indicator connected between said first output terminal and ground.
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) | 1981-09-04 | 1982-03-06 | 1982-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-04 | 1986-03-06 | 1986-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-04 | 1990-03-06 | 1990-09-05 | $7700.00 | Window Closed / Lapsed |