US3979564A
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4-Channel stereo recording and reproducing method
Assignee: Pioneer Corp
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Filing: 1973-03-08
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Granted: 1976-09-07
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Expires: 1993-03-08
Abstract
Abstract A method for recording and reproducing a 4-channel stereo signal wherein the reproduced signal can be used with conventional discrete signal or matrix stereophonic systems. Four related audio signals are matrixed to produce a first main channel audio signal, a first sub-channel audio signal, a second main channel signal and a second sub-channel audio signal. The sub-channel signals are modulated, and the first main channel signal and the modulated first sub-channel signal are recorded on one recording surface of a record. The second main channel signal and modulated second sub-channel signal are recorded on another recording surface of the record. To reproduce the original four related audio signals, the first and second sub-channel signals are demodulated and the first main channel signal, first sub-channel signal, second main channel signal, and second sub-channel signal are matrixed to produce the four related audio signals. The matrix is arranged such that if only the main channel signals are applied to the matrix, an output compatible with a conventional matrix stereophonic system will be produced. If, however, all four signals are applied to the matrix, an output compatible with prior discrete stereo signal systems is produced.
Inventors
- 👤 Mayumi Cho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:09
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H04H20/89; H04S; H04S3/00; H04S3/006
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
247 words
A method of recording and reproducing a four channel stereo signal on a record comprising: a. generating four related audio signals; b. matrixing said four audio signals to produce a first main channel audio signal composed of at least three of said four related audio signals in a first predetermined phase and amplitude relationship, a first sub-channel audio signal composed of at least two of said four related audio signals in a second predetermined phase and amplitude relationship, a second main channel audio signal composed of at least three of said four related audio signals in a third predetermined phase and amplitude relationship, and a second sub-channel audio signal composed of at least two of said four related audio signals in a fourth predetermined phase and amplitude relationship, c. frequency modulating a carrier wave with said first sub-channel audio signal; d. frequency modulating a carrier wave with said second sub-channel audio signal; e. recording said first main channel audio signal and said carrier modulated by said first sub-channel audio signal on a first recording surface of said record; f. recording said second main channel audio signal and said carrier modulated by said second sub-channel audio signal on a second recording surface of said record; g. reproducing said first and second main channel audio signals and said first and second sub-channel audio signals to produce four separate audio signals capable of being applied to a matrix or discrete stereophonic reproducing system for providing said four channel stereo signal.
Claim 2
Independent Claim
247 words
A method of recording and reproducing a four channel stereo signal on a record comprising: a. generating four related audio signals; b. matrixing said four audio signals to produce a first main channel audio signal composed of at least three of said four related audio signals in a first predetermined phase and amplitude relationship, a first sub-channel audio signal composed of at least two of said four related audio signals in a second predetermined phase and amplitude relationship, a second main channel audio signal composed of at least three of said four related audio signals in a third predetermined phase and amplitude relationship, and a second sub-channel audio signal composed of at least two of said four related audio signals in a fourth predetermined phase and amplitude relationship, c. frequency modulating a carrier wave with said first sub-channel audio signal; d. frequency modulating a carrier wave with said second sub-channel audio signal; e. recording said first main channel audio signal and said carrier modulated by said first sub-channel audio signal on a first recording surface of said record; f. recording said second main channel audio signal and said carrier modulated by said second sub-channel audio signal on a second recording surface of said record; g. reproducing said first and second main channel audio signals and said first and second sub-channel audio signals to produce four separate audio signals capable of being applied to a matrix or discrete stereophonic reproducing system for providing said four channel stereo signal.
Claim 3
Dependent Claim
69 words
The method of claim 1, wherein reproducing said first and second main channel audio signals and said first and second sub-channel audio signals includes: a. demodulating said carrier to produce said first and second sub-channel audio signals; b. matrixing said first main channel audio signal, said first sub-channel audio signal, said second main channel audio signal, and said second sub-channel audio signal to produce said four channel stereo signal.
Claim 4
Dependent Claim
147 words
The method of claim 1, wherein said first main channel audio signal is composed of only three of said four related audio signals and said first sub-channel audio signal is composed of the same three audio signals as said first main channel audio signal, two of said audio signals in said first sub-channel audio signal being equal in amplitude and in phase opposition to the corresponding two audio signals in said first main channel audio signal, and wherein said second main channel audio signal is composed of a different combination of three audio signals and said second sub-channel audio signal is composed of the same three audio signals as said second main channel audio signal, two of said audio signals in said second sub-channel audio signal being equal in amplitude and in phase opposition to the corresponding two audio signals in said second main channel audio signal.
Claim 5
Dependent Claim
136 words
The method of claim 3, wherein reproducing said first and second main channel audio signals and said first and second sub-channel audio signals includes: a. demodulating said carrier to produce said first and second sub-channel audio signals; b. matrixing said first main channel audio signal with said first sub-channel audio signal to produce one of said four related audio signals and a first composite signal composed of the remaining two of the three audio signals of said first main channel and first sub-channel audio signals, and c. matrixing said second main channel audio signal with said second sub-channel audio signal to produce a second one of said four related audio signals and a second composite signal composed of the remaining two of the three audio signals of said second main channel and second sub-channel audio signals.
Claim 6
Dependent Claim
31 words
The method of claim 4, wherein the step of reproducing further includes matrixing said first and second composite signals to produce the third and fourth of said four related audio signals.
Claim 7
Dependent Claim
141 words
The method of claim 1, wherein said first main channel audio signal is composed of all four of said four related audio signals and said first sub-channel audio signal is composed of only two of said four related audio signals, one of said audio signals in said first sub-channel audio signal being equal in amplitude and in phase opposition to the corresponding audio signal in said first main channel audio signal, and wherein said second main channel audio signal is composed of all four of said four related audio signals and said second sub-channel audio signal is composed of a different two audio signals than said first sub-channel audio signal, one of said audio signals in said second sub-channel audio signal being equal in amplitude and in phase opposition to the corresponding audio signal in said second main channel audio signal.
Claim 8
Dependent Claim
97 words
The method of claim 6, wherein reproducing said first and second main channel audio signals and said first and second sub-channel audio signals includes: a. demodulating said carrier to produce said first and second sub-channel audio signals; b. matrixing said first main channel audio signal with said first sub-channel audio signal to produce first and second composite signals, and c. matrixing said second main channel audio signal with said second sub-channel audio signal to produce third and fourth composite signals, each of said four related audio signals being substantially dominant in respective ones of said composite signals.
Claim 9
Dependent Claim
61 words
The method of claim 7, wherein the step of reproducing further includes: a. matrixing said first and second composite signals with said second sub-channel audio signal to produce two of said four related audio signals, and b. matrixing said third and fourth composite signals with said first sub-channel audio signal to produce the other two of said four related audio signals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |