US3582791A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna coupling and tuning circuit
Assignee: Bendix Corp
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Filing: 1968-12-11
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Granted: 1971-06-01
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Expires: 1988-12-11
Abstract
Abstract A circuit for coupling an antenna to the input circuit of a radio receiver is described. The inventive circuit is particularly useful with the whip type of antenna ordinarily employed with mobile vehicles having AM and/or FM radio receivers. A field effect transistor is placed in the base of the antenna, and the signal received by the antenna is coupled to the input circuit through the FET. For this reason, changing the length of the antenna has no effect on the tuning of the circuit. Coupling to the RF amplifier of the receiver is done by means of a unique coupling including a complex reactance circuit. The circuit is voltage tuned by the use of a voltage sensitive capacitor.
Inventors
- 👤 Michael Slavin
- 👤 Peter Manson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:27
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/22; H04B1/24
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
151 words
An antenna circuit for use with an antenna and a receiver comprising: an electron control device situated in the proximity of said antenna and receiving an input therefrom, the output of said electron control device being coupled to said tuning circuit by coupling means, said tuning circuit being remotely situated with respect to said antenna, said coupling means being magnetic coupling means including first and second inductive elements; said tuning circuit further including voltage sensitive reactance means for tuning said circuit to a desired frequency, a first terminal of said voltage sensitive reactance means being connected to a first terminal of said second inductive element; and frequency variable reactance means connected between a second terminal of said voltage sensitive reactance means and a second terminal of said second inductive element to form a resonant circuit including said second inductive element, said voltage sensitive reactance means and said frequency variable reactance means.
Claim 2
Dependent Claim
151 words
An antenna circuit for use with an antenna and a receiver comprising: an electron control device situated in the proximity of said antenna and receiving an input therefrom, the output of said electron control device being coupled to said tuning circuit by coupling means, said tuning circuit being remotely situated with respect to said antenna, said coupling means being magnetic coupling means including first and second inductive elements; said tuning circuit further including voltage sensitive reactance means for tuning said circuit to a desired frequency, a first terminal of said voltage sensitive reactance means being connected to a first terminal of said second inductive element; and frequency variable reactance means connected between a second terminal of said voltage sensitive reactance means and a second terminal of said second inductive element to form a resonant circuit including said second inductive element, said voltage sensitive reactance means and said frequency variable reactance means.
Claim 3
Dependent Claim
28 words
The antenna tuning circuit of claim 1 wherein said electron control means is a field effect transistor which isolates said tuning circuit from capacitance change of said antenna.
Claim 4
Dependent Claim
25 words
The antenna tuning circuit of claim 1 further including means for coupling an automatic gain control signal to the input of said electron control device.
Claim 5
Dependent Claim
26 words
The antenna tuning circuit of claim 3 further including a variable voltage source associated with said voltage sensitive reactance element to selectively change the reactance thereof.
Claim 6
Dependent Claim
31 words
The antenna tuning circuit of claim 4 wherein said voltage sensitive reactance element is a capacitive element the capacitance of which varies proportionally to the variance of said variable voltage source.
Claim 7
Dependent Claim
35 words
The antenna tuning circuit of claim 5 wherein said frequency variable reactance means includes the serial combination of a fixed capacitor and a fixed iNductor, said serial combination being serially connected to said capacitive element.
Claim 8
Dependent Claim
27 words
The antenna tuning circuit of claim 6 wherein the output from said tuning circuit is taken from the junction of said capacitive element and said series combinations.
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) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |