US3919645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
AM/FM radio receiver
Assignee: Sony Corp
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Filing: 1974-06-06
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Granted: 1975-11-11
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Expires: 1994-06-06
Abstract
Abstract An AM/FM radio receiver has an FM input circuit and an FM amplifier connected to a rectifier circuit and has an AM input circuit and an AM intermediate frequency amplifier also connected to the same rectifier circuit. Either AM intermediate frequency signals or FM intermediate freuqency signals actuate the rectifier to produce a direct current signal, and the rectifier is connected to a tuning indicator so that the direct current signal actuates the indicator to identify correct tuning of either the AM input circuit or the FM input circuit. The rectifier is also connected to another circuit to control an automatic mono-stereo switching circuit in the FM portion of the receiver to allow stereo operation if the incoming signal has a sufficiently high amplitude. The signal from the rectifier is also connected to a muting circuit to mute the output of the FM section of the receiver in the absence of any FM signals. The output of the rectifier is also connected to a gain control circuit in the AM intermediate frequency amplifier to provide automatic gain control of the AM section of the receiver.
Inventors
- 👤 Mitsuo Ohsawa
- 👤 Yukio Onoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:11
CPC Classifications
H; H04; H04H; H04H40/00; H04H40/18; H04H40/27; H04H40/36; H04H40/45; H03; H03D; H03D5/00; H03J; H03J3/00; H03J3/02; H03J3/12; H03J3/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
382 words
An AM/FM radio receiver for selectively reproducing audio information transmitted thereto by AM or FM transMission, comprising: a tunable FM section for receiving an FM signal and including an FM intermediate frequency amplifier, an FM demodulator coupled to said FM intermediate frequency amplifier, and output means coupled to said FM demodulator for receiving said audio information; a tunable AM section separate from said FM section for receiving an AM signal and including a gain controllable AM intermediate frequency amplifier, an AM demodulator coupled to said AM intermediate frequency amplifier, and output means coupled to said AM demodulator for receiving said audio information; first coupling means coupled to said FM intermediate frequency amplifier for receiving the FM intermediate frequency signal and for coupling same to further means; second coupling means coupled to said AM intermediate frequency amplifier for receiving the AM intermediate frequency signal and for coupling same to said further means; portions of said first and second coupling means being connected in series with each other, the impedance of said first coupling means to said AM intermediate frequency signal being relatively low such that substantially no attenuation is imparted thereby to said AM intermediate frequency signal, and the impedance of said second coupling means to said FM intermediate frequency signal being relatively low such that substantially no attenuation is imparted thereby to said FM intermediate frequency signal; a transistor having its base-emitter circuit connected in series with said portions of said first and second coupling means to receive said FM and AM intermediate frequency signals, the base-emitter junction of said transistor rectifying the signals applied thereto to produce a direct current having a magnitude determined by the amplitude of said applied signals; indicating means connected to the collector of said transistor for indicating the magnitude of said produced direct current to thereby indicate the tuning condition of said receiver with respect to the received FM and AM signals; and means coupled to the emitter of said transistor and responsive to said magnitude of said produced direct current to control the gain of said AM intermediate frequency amplifier and to control the operation of said FM section output means so as to permit the stereo reproduction of a received stereo FM signal and to permit interstation muting during tuning of said FM section.
Claim 2
Dependent Claim
382 words
An AM/FM radio receiver for selectively reproducing audio information transmitted thereto by AM or FM transMission, comprising: a tunable FM section for receiving an FM signal and including an FM intermediate frequency amplifier, an FM demodulator coupled to said FM intermediate frequency amplifier, and output means coupled to said FM demodulator for receiving said audio information; a tunable AM section separate from said FM section for receiving an AM signal and including a gain controllable AM intermediate frequency amplifier, an AM demodulator coupled to said AM intermediate frequency amplifier, and output means coupled to said AM demodulator for receiving said audio information; first coupling means coupled to said FM intermediate frequency amplifier for receiving the FM intermediate frequency signal and for coupling same to further means; second coupling means coupled to said AM intermediate frequency amplifier for receiving the AM intermediate frequency signal and for coupling same to said further means; portions of said first and second coupling means being connected in series with each other, the impedance of said first coupling means to said AM intermediate frequency signal being relatively low such that substantially no attenuation is imparted thereby to said AM intermediate frequency signal, and the impedance of said second coupling means to said FM intermediate frequency signal being relatively low such that substantially no attenuation is imparted thereby to said FM intermediate frequency signal; a transistor having its base-emitter circuit connected in series with said portions of said first and second coupling means to receive said FM and AM intermediate frequency signals, the base-emitter junction of said transistor rectifying the signals applied thereto to produce a direct current having a magnitude determined by the amplitude of said applied signals; indicating means connected to the collector of said transistor for indicating the magnitude of said produced direct current to thereby indicate the tuning condition of said receiver with respect to the received FM and AM signals; and means coupled to the emitter of said transistor and responsive to said magnitude of said produced direct current to control the gain of said AM intermediate frequency amplifier and to control the operation of said FM section output means so as to permit the stereo reproduction of a received stereo FM signal and to permit interstation muting during tuning of said FM section.
Claim 3
Dependent Claim
44 words
An AM/FM radio receiver in accordance with claim 1 wherein said FM section output means comprises a stereo-multiplex circuit having monaural/stereo switch means; a muting circuit; and means for applying said produced direct current to siad monaural/stereo switch means and to said muting circuit.
Claim 4
Dependent Claim
46 words
An AM/FM radio receiver according to claim 1 wherein each of said coupling means is comprised of a tuned circuit having primary and secondary windings, a secondary winding of each of said tuned circuits being connected in series with each other and connected to said transistor.
Claim 5
Dependent Claim
38 words
An AM/FM radio receiver according to claim 3 wherein said second coupling means further includes a capacitor connected in parallel with said secondary winding, said capacitor having a relatively low impedance with respect to FM intermediate frequency signals.
Claim 6
Dependent Claim
31 words
An AM/FM radio receiver according to claim 3 wherein said tuned circuit included in said first coupling means has a bandpass characteristic narrower than that of said FM intermediate frequency amplifier.
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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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |