US3852686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic frequency control circuit
Assignee: Sony Corp
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Filing: 1973-11-21
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Granted: 1974-12-03
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Expires: 1993-11-21
Abstract
Abstract An automatic frequency control circuit includes a transistor, an L-C resonant circuit connected to the transistor to form an oscillator and a varicap diode which is supplied with an automatic frequency control voltage signal and is reverse biased by a bias voltage received from the collector electrode of the transistor. The bias voltage provided by the transistor is constant so that the varicap diode is inhibited from performing a rectifying operation on the oscillating signal produced by the oscillator.
Inventors
- 👤 K Morii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:33
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03J7/04; H03J7/08; H03B; H03B5/00; H03B5/08; H03B5/12; H03B5/1203; H03B5/1231; H03B5/1237; H03B5/124; H03B5/1293; H03B5/1296; H03B2200/00; H03B2200/0002; H03B2200/001
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
130 words
An automatic frequency control circuit, comprising: an L-C resonant circuit; a transistor connected to said L-C resonant circuit to thereby form an oscillator circuit, said transistor including a collector electrode connected to the base electrode thereof by a DC feedback path; a source of energizing potential coupled to the collector electrode of said transistor by first resistance means for supplying an energizing potential thereto; varicap diode means connected in AC parallel relationship to the capacitance means of said L-C resonant circuit, said varicap diode means being further connected to the collector electrode of transistor to receive a reverse bias voltage therefrom; and means for supplying a frequency controlling signal to said varicap diode means to vary the capacitance thereof, whereby the oscillating frequency of said oscillating circuit is correspondingly varied.
Claim 2
Dependent Claim
130 words
An automatic frequency control circuit, comprising: an L-C resonant circuit; a transistor connected to said L-C resonant circuit to thereby form an oscillator circuit, said transistor including a collector electrode connected to the base electrode thereof by a DC feedback path; a source of energizing potential coupled to the collector electrode of said transistor by first resistance means for supplying an energizing potential thereto; varicap diode means connected in AC parallel relationship to the capacitance means of said L-C resonant circuit, said varicap diode means being further connected to the collector electrode of transistor to receive a reverse bias voltage therefrom; and means for supplying a frequency controlling signal to said varicap diode means to vary the capacitance thereof, whereby the oscillating frequency of said oscillating circuit is correspondingly varied.
Claim 3
Dependent Claim
45 words
An automatic frequency control circuit in accordance with claim 1 wherein said transistor is connected to said L-C resonant circuit to form a Hartley-type oscillator circuit and wherein the DC feedback path interconnecting the collector and base electrodes of the transistor comprises second resistance means.
Claim 4
Dependent Claim
44 words
An automatic frequency control circuit in accordance with claim 2 further including signal output means Transformer coupled to the inductance means of said L-C resonant circuit; and a control signal input terminal coupled to said varicap diode means to receive said frequency controlling signal.
Claim 5
Dependent Claim
26 words
An automatic frequency control circuit in accordance with claim 1 wherein said transistor is connected to said L-C resonant circuit to form a Colpitts-type oscillator circuit.
Claim 6
Dependent Claim
71 words
An automatic frequency control circuit in accordance with claim 4 further including signal output means comprising a first inductor and a first capacitor connected in series between the collector electrode of said transistor and a source of reference potential, wherein an output signal is derived from the signal produced by said first inductor; and a control signal input terminal coupled to said varicap diode means to receive said frequency controlling signal.
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) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |