Patent US4397041A successfully refreshed from Google Patents.
US4397041A
Expired / Lapsed
US
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Complex antenna system and FM/AM receiver
Assignee: Pioneer Corp
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Filing: 1981-03-03
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Granted: 1983-08-02
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Expires: 2001-03-03
Abstract
Abstract A complex antenna system including at least two loop antennas crossing each other and connected with each other at the electric neutral points thereof, and a rod antenna positioned at the central portion of the loop antennas. An FM and/or AM tuners combined with the complex antenna system utilizes selected one of the loop antennas for receiving an FM wave so as to avoid multi-path noises.
Inventors
- 👤 Shigeki Takeda
- 👤 Junichi Shibata
- 👤 Masashi Shimakata
- 👤 Yasuhiro Oshime
- 👤 Shintaro Gomi
- 👤 Katsuaki Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:46
CPC Classifications
H; H01; H01Q; H01Q5/00; H01Q5/40
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
117 words
An FM receiver comprising an FM tuner (13); an antenna system (1), said antenna system including at least two loop antennas crossing each other and connected with each other at the electric neutral points thereof and having the output terminals thereof positioned closely to each other; a multipath noise detector (17) connected to said FM tuner for producing a change-over signal when it detects the multipath noises; at least two impedance matching circuits (10a, 10b) having the input terminals thereof respectively connected to the output terminals of said loop antennas; and a switching circuit (12) for alternately connecting either one of the output terminal of said impedance matching circuits to the input terminal of said FM tuner.
Claim 2
Dependent Claim
117 words
An FM receiver comprising an FM tuner (13); an antenna system (1), said antenna system including at least two loop antennas crossing each other and connected with each other at the electric neutral points thereof and having the output terminals thereof positioned closely to each other; a multipath noise detector (17) connected to said FM tuner for producing a change-over signal when it detects the multipath noises; at least two impedance matching circuits (10a, 10b) having the input terminals thereof respectively connected to the output terminals of said loop antennas; and a switching circuit (12) for alternately connecting either one of the output terminal of said impedance matching circuits to the input terminal of said FM tuner.
Claim 3
Dependent Claim
22 words
An FM receiver as claimed in claim 1, wherein the maximum sensitivity directions of said loop antennas locate equiangularly to each other.
Claim 4
Dependent Claim
19 words
An FM receiver as claimed in claim 1, wherein said loop antennas cross each other rectangularly to each other.
Claim 5
Dependent Claim
73 words
An FM receiver as claimed in claim 1, wherein said switching circuit (12) includes at least two amplifiers (50, 51, 54, 55) having the input terminals thereof respectively connected to the output terminals of said impedance matching circuits and having the output terminals thereof connected to the input terminals of said FM tuner, and a change-over circuit (53, 56) connected to said amplifiers (50, 51, 54, 55) for making said amplifiers alternately operative.
Claim 6
Dependent Claim
36 words
An FM receiver as claimed in claim 4, wherein said change-over circuit is a change-over switch element (53) for supplying alternately one of said amplifiers with a source voltage (+B) in accordance with said change-over signal.
Claim 7
Dependent Claim
61 words
An FM receiver as claimed in claim 4, wherein said amplifiers are variable gain amplifiers (54, 55) each having a gain according to a control voltage applied thereto, and said change-over circuit includes a gain controller (56) for controlling the gain of said amplifiers so as to make substantially operative alternatively one of said amplifiers in response to said change-over signal.
Claim 8
Dependent Claim
50 words
An FM receiver as claimed in claim 1, further comprising a case element supporting thereon said antenna system and carrying therein said impedance matching circuits; and support means connected to said case element for fastening said case element to a body on which the FM receiver is to be mounted.
Claim 9
Dependent Claim
18 words
An FM receiver as claimed in claim 7, wherein said case element also carries therein said switching circuit.
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) | 1986-08-01 | 1987-01-31 | 1987-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-01 | 1991-01-31 | 1991-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-01 | 1995-01-31 | 1995-08-02 | $7700.00 | Window Closed / Lapsed |