US4034158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Quadraphonic passive four-channel decoder
Assignee: Individual
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Filing: 1972-12-05
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Granted: 1977-07-05
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Expires: 1992-12-05
Abstract
Abstract A quadraphonic decoder is described for providing connections between a stereo amplifier and four loudspeakers. Two signals each comprising in-phase and out-of-phase components are applied from the amplifier to the speakers by the decoder so that these four separable components are each reproduced by a different loudspeaker. Means are provided for trapping out-of-phase signal components off the speakers reproducing in-phase signal information. A different network is provided to allow the speakers reproducing out-of-phase signals to operate independently. Means are also provided for damping out all but the out-of-phase signal components on the speakers, so that the presence of such signal components may be detected.
Inventors
- 👤 Berdette O. Britton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:29
CPC Classifications
H; H04; H04S; H04S5/00; H04S5/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
349 words
A decoding network for use in a quadraphonic sound system connected between the left and right outputs of a stereophonic amplifier and at least four acoustic transducers, the respective left and right audio output signals of that amplifier each having signal components in phase with one another and also signal components out of phase with the corresponding signal components of the other, comprising means for applying said left audio output signal from said left amplifier output to a left pair of said acoustic transducers, means for applying said right audio output signal from said right amplifier output to a right pair of said acoustic transducers, means connecting the first of said left pair and the first of said right pair of transducers in series with said left and right amplifier outputs so that said first transducer of each pair responds primarily to the mutually out-of-phase components of the respective applied audio signals, means connecting the second of said left pair and the second of said right pair of transducers respectively across the respective said left and right amplifier outputs, trap means comprising a pair of series connected resistors, said resistor pair being center tapped, and said resistor pair being connected in series between the high sides of only said second left and right transducers, whereby the out-of-phase components of the left and right audio signals substantially cancel each other out and are not reproduced by said second transducers, a differentiating network coupled between said transducer series connecting means and ground so that each one of said series connected first pair of acoustic transducers is responsive to its out-of-phase component and to a portion of its respective in-phase component of the audio signal applied thereto, and a switch for selectively connecting said resistor center tap to ground, whereby, when the center tap is connected to ground, there is provided an in-phase amplifier load sufficient to permit application of only the out-of-phase signal component and only to said second transducers, without destructive oscillation of the amplifier, such that the presence or absence of such an out-of-phase signal component may be detected.
Claim 2
Dependent Claim
349 words
A decoding network for use in a quadraphonic sound system connected between the left and right outputs of a stereophonic amplifier and at least four acoustic transducers, the respective left and right audio output signals of that amplifier each having signal components in phase with one another and also signal components out of phase with the corresponding signal components of the other, comprising means for applying said left audio output signal from said left amplifier output to a left pair of said acoustic transducers, means for applying said right audio output signal from said right amplifier output to a right pair of said acoustic transducers, means connecting the first of said left pair and the first of said right pair of transducers in series with said left and right amplifier outputs so that said first transducer of each pair responds primarily to the mutually out-of-phase components of the respective applied audio signals, means connecting the second of said left pair and the second of said right pair of transducers respectively across the respective said left and right amplifier outputs, trap means comprising a pair of series connected resistors, said resistor pair being center tapped, and said resistor pair being connected in series between the high sides of only said second left and right transducers, whereby the out-of-phase components of the left and right audio signals substantially cancel each other out and are not reproduced by said second transducers, a differentiating network coupled between said transducer series connecting means and ground so that each one of said series connected first pair of acoustic transducers is responsive to its out-of-phase component and to a portion of its respective in-phase component of the audio signal applied thereto, and a switch for selectively connecting said resistor center tap to ground, whereby, when the center tap is connected to ground, there is provided an in-phase amplifier load sufficient to permit application of only the out-of-phase signal component and only to said second transducers, without destructive oscillation of the amplifier, such that the presence or absence of such an out-of-phase signal component may be detected.
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) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |