US3673342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangement for improving the signal-to-noise ratio of a stereo decoder
Assignee: Interessengemeinschaft fuer Rundfunkschutzrechte GmbH Schutzrechtsverwertung and Co KG
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Filing: 1970-07-30
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Granted: 1972-06-27
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Expires: 1990-07-30
Abstract
Abstract A variable resistor, a photoconductor shone upon by an incandescent lamp the brightness of which is inversely proportional to the carrier strength, or a variable time constant RC-network is connected to the stereo decoder to vary the stereo separation in direct proportion to the carrier strength.
Inventors
- 👤 Karl Muller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:35
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1646; H04B1/1653
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
106 words
In an FM stereo receiver, in combination, decoder means having at its output a first and a second audio channel, and adapted to convert a received broadcast FM stereo carrier signal into first and second signals respectively appearing at said first and second channels and constituting the left and right signals of a stereo audio output; and circuit means operatively associated with said decoder means for continuously varying the degree of separation between said left and right signals in dependence upon the strength of the carrier signal received, whereby to effect smooth transitions between mono and stereo reproduction with concomitant substantially smooth variations in output noise.
Claim 2
Dependent Claim
106 words
In an FM stereo receiver, in combination, decoder means having at its output a first and a second audio channel, and adapted to convert a received broadcast FM stereo carrier signal into first and second signals respectively appearing at said first and second channels and constituting the left and right signals of a stereo audio output; and circuit means operatively associated with said decoder means for continuously varying the degree of separation between said left and right signals in dependence upon the strength of the carrier signal received, whereby to effect smooth transitions between mono and stereo reproduction with concomitant substantially smooth variations in output noise.
Claim 3
Dependent Claim
20 words
An arrangement as defined in claim 1, wherein said circuit means comprise variable resistance means connected between said audio channels.
Claim 4
Dependent Claim
37 words
An arrangement as defined in claim 2, wherein said variable resistance means comprise photoconductor means, and incandescent lamp means connected to be energized in dependence on the strength of the received carrier, and illuminating said photoconductor means.
Claim 5
Dependent Claim
31 words
An arrangement as defined in claim 3, including energizing means for energizing said lamp in inverse proportion to the strength of the received carrier, and wherein said photosensitive means are photoconductive.
Claim 6
Dependent Claim
23 words
An arrangement as defined in claim 4, wherein said energizing means comprises amplifying means connected to a non-limiting stage of an FM receiver.
Claim 7
Dependent Claim
52 words
An arrangement as defined in claim 1, wherein said circuit means are frequency filter means in circuit with the decoder for reducing the bandwidth of the modulated subcarrier in dependence on the strength of the received carrier, whereby to change the stereo separation in dependence on the strength of the received carrier.
Claim 8
Dependent Claim
17 words
An arrangement as defined in claim 6, wherein said filter means comprise a variable time constant RC-network.
Claim 9
Dependent Claim
36 words
An arrangement as defined in claim 6, wherein said filter means comprises photosensitive means and incandescent lamp means connected to be energized in dependence on the strength of the received carrier and illuminating said photosensitive means.
Claim 10
Dependent Claim
32 words
An arrangement as defined in claim 8, wherein said photosensitive means are photoconductive, and further including energizing means for energizing said lamp in inverse proportion to the strength of the received carrier.
Claim 11
Dependent Claim
31 words
An arrangement as defined in claim 8, wherein said photosensitive means are photoconductive, and including energizing means for energizing said lamp in direct proportion to the strength of the received carrier.
Claim 12
Dependent Claim
23 words
An arrangement as defined in claim 9, wherein said energizing means are amplifying means connected to a non-limiting stage of an FM receiver.
Claim 13
Dependent Claim
18 words
An arrangement as defined in claim 7, wherein said RC-network is connected in the input of the decoder.
Claim 14
Dependent Claim
14 words
An arrangement as defined in claim 7, wherein said RC-network includes variable potentiometer means.
References Cited (Backward Citations)
DE1286566B
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |