Patent US3736638A successfully refreshed from Google Patents.
US4232191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
FM Receiving device
Assignee: Trio KK
•
Filing: 1978-02-17
•
Granted: 1980-11-04
•
Expires: 1998-02-17
Abstract
Abstract A double super heterodyne FM receiver having a first local oscillator for deriving a first intermediate frequency signal from an FM input signal, tuning means for varying the frequency of the first local oscillator to tune the FM receiver to a predetermined frequency, a second local oscillator for deriving a second intermediate frequency signal from the first intermediate frequency signal, an FM detector for demodulating the second intermediate frequency and means for processing the demodulated signal, means for deriving the direct current component of an output signal occurring at a point after the FM detector, first control means for controlling the frequency of the second oscillator in response to the direct current component so that the direct current component is reduced to substantially zero to thereby lessen shock noise during the tuning of the receiver, second control means responsive to the tuning means being operated to tune the FM receiver so that the control means controls the means for deriving the direct current component to thereby derive a first low frequency range as the direct current component, the control means also being responsive to the tuning means no longer being operated so that a second low frequency range less than the first low frequency range is derived as the direct current component. The receiver may also include a stereo demodulator whereby shock noise and accordingly multi-stage coupling capacitance in the output stages may be eliminated by feeding the direct current component back from a point after the stereo demodulator to control the frequency of the second oscillator.
Inventors
- 👤 Takeshi Matsuzuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:30
CPC Classifications
H; H04; H04H; H04H40/00; H04H40/18; H04H40/27; H04H40/36; H04H40/45; H04H40/72; H03; H03D; H03D7/00; H03D7/16; H03D7/161; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/348; H03J; H03J7/00; H03J7/02; H03J7/023
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
162 words
A double super heterodyne, stereo FM receiver comprising a first local oscillator; a first mixer responsive to an FM stereo input signal and the output from said first local oscillator for deriving a first intermediate frequency signal; a second local oscillator; a second mixer responsive to said first intermediate frequency signal and the output from said second local oscillator for deriving a second intermediate frequency signal; an FM detector for demodulating the second intermediate frequency signal; a stereo demodulator DC coupled to said FM detector and responsive to the demodulated output signal from said FM detector for deriving left and right audio signals, said stereo demodulator being capable of passing a DC component from the FM detector: and means for controlling the frequency of said second local oscillator in response to said DC component taken from a point after said stereo demodulator so that the DC component is reduced to substantially zero to thereby lessen shock noise during tuning of the receiver.
Claim 2
Dependent Claim
162 words
A double super heterodyne, stereo FM receiver comprising a first local oscillator; a first mixer responsive to an FM stereo input signal and the output from said first local oscillator for deriving a first intermediate frequency signal; a second local oscillator; a second mixer responsive to said first intermediate frequency signal and the output from said second local oscillator for deriving a second intermediate frequency signal; an FM detector for demodulating the second intermediate frequency signal; a stereo demodulator DC coupled to said FM detector and responsive to the demodulated output signal from said FM detector for deriving left and right audio signals, said stereo demodulator being capable of passing a DC component from the FM detector: and means for controlling the frequency of said second local oscillator in response to said DC component taken from a point after said stereo demodulator so that the DC component is reduced to substantially zero to thereby lessen shock noise during tuning of the receiver.
Claim 3
Dependent Claim
24 words
A receiver as in claim 1 including output amplifiers DC coupled to said stereo amplifier for respectively amplifying said left and right audio signals.
Claim 4
Dependent Claim
25 words
A receiver as in claim 2 where said DC component is at least one of the output signals from said first and second output amplifiers.
Claim 5
Dependent Claim
23 words
In a receiver as in claim 3 where said DC component is both said output signals from said first and second output amplifiers.
Claim 6
Dependent Claim
21 words
A receiver as in claim 1 where said DC component is at least one of said right and left audio signals.
Claim 7
Dependent Claim
19 words
A receiver as in claim 5 where said DC component is both of said right and left audio signals.
Claim 8
Dependent Claim
20 words
A receiver as in claim 1 where said DC component is the sum of said left and right audio signals.
Claim 9
Dependent Claim
240 words
A double super heterodyne FM receiver comprising a first local oscillator; a first mixer responsive to an FM input signal and the output from said first local oscillator for deriving a first intermediate frequency signal; tuning means for varying the frequency of said first local oscillator to tune said FM receiver to a predetermined frequency; a second local oscillator; a second mixer responsive to said first intermediate frequency signal and the output of said second local oscillator for deriving a second intermediate frequency signal; an FM detector for demodulating the second intermediate frequency; means for processing the demodulated signal; means for deriving a direct current component of an output signal occurring at a point after said FM detector, said direct current component having at least a predetermined frequency range extending from substantially zero frequency; control means for controlling the frequency of said second oscillator in response to said direct current component so that the direct current component is reduced to substantially zero to thereby lessen shock noise during the tuning of the receiver said control means being responsive to said tuning means being operated to tune said FM receiver so that said means for deriving the direct current component derives said predetermined frequency range as said direct current component, said control means also being responsive to the tuning means not being operated so that a frequency range less than said predetermined frequency range is derived as said direct current component.
Claim 10
Dependent Claim
240 words
A double super heterodyne FM receiver comprising a first local oscillator; a first mixer responsive to an FM input signal and the output from said first local oscillator for deriving a first intermediate frequency signal; tuning means for varying the frequency of said first local oscillator to tune said FM receiver to a predetermined frequency; a second local oscillator; a second mixer responsive to said first intermediate frequency signal and the output of said second local oscillator for deriving a second intermediate frequency signal; an FM detector for demodulating the second intermediate frequency; means for processing the demodulated signal; means for deriving a direct current component of an output signal occurring at a point after said FM detector, said direct current component having at least a predetermined frequency range extending from substantially zero frequency; control means for controlling the frequency of said second oscillator in response to said direct current component so that the direct current component is reduced to substantially zero to thereby lessen shock noise during the tuning of the receiver said control means being responsive to said tuning means being operated to tune said FM receiver so that said means for deriving the direct current component derives said predetermined frequency range as said direct current component, said control means also being responsive to the tuning means not being operated so that a frequency range less than said predetermined frequency range is derived as said direct current component.
Claim 11
Dependent Claim
32 words
A receiver as in claim 8 where said means for deriving the direct current component comprises a resistor and capacitor in circuit where the direct current component is taken from the capacitor.
Claim 12
Dependent Claim
15 words
A receiver as in claim 9 where the receiver includes a touch switch tuning knob.
Claim 13
Dependent Claim
21 words
A receiver as in claim 10 where said resistor is varied in response to said tuning knob being touched and released.
References Cited (Backward Citations)
US2282834A
Cited
US2272401A
Cited
US3257511A
Cited
US3742361A
Cited
US3909735A
Cited
US3965423A
Cited
US4092602A
Cited
US4142158A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-04 | 1984-05-05 | 1984-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-04 | 1988-05-05 | 1988-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-04 | 1992-05-05 | 1992-11-04 | $7700.00 | Window Closed / Lapsed |