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US3794780A
Expired / Lapsed
US
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Quadraphonic recording system
Assignee: CBS Broadcasting Inc
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Filing: 1972-07-13
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Granted: 1974-02-26
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Expires: 1992-07-13
Abstract
Abstract Apparatus for recording four separate channels of sound information on the two tracks of a stereophonic disc record for subsequent reproduction on four loudspeakers to give the listener the illusion of sound coming from four separate sources. Two of the four signals are applied to respective ones of the two tracks, as in stereophonic recording, with the third and fourth channels superimposed thereon by applying equal in-phase portions of the third signal to both of the tracks and by applying equal portions of the fourth signal to both of the tracks with a differential phase angle between the two portions which remains substantially constant throughout the audio frequency range of interest. The fourth signal applied in this way causes the stylus of a stereophonic cutter to describe an ellipse having major vertical and horizonal axes disposed normal and parallel, respectively, to the surface of the record.
Inventors
- 👤 B Bauer
- 👤 D Gravereaux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:28
CPC Classifications
H; H04; H04S; H04S3/00; H04S3/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
195 words
Apparatus for transforming a multi-channel program including at least first, second and third separate audio program signals into two composite signals, said apparatus comprising, at least first, second and third input terminals to which said separate first, second and third program signals are respectively applied, first and second output terminals, means connected between said first and second input terminals and said first and second output terminals, respectively, operative to transfer substantially equal amplitude proportions of said first and second program signals without relative phase change to said first and second output terminals, respectively, and means connected between said third input terminal and both said first and second output terminals operative to transfer substantially equal reduced amplitude proportions of said third program signal to both said first and second output terminals and including phase-shifting means operative to provide a differential phase-shift angle between the proportion of said third program signal transferred to said first terminal and the proportion of said third program signal transferred to said second output terminal, which phase-shift angle has a value in the range between 110* and 170* and remains substantially constant over the range of frequencies of said third program signal.
Claim 2
Dependent Claim
195 words
Apparatus for transforming a multi-channel program including at least first, second and third separate audio program signals into two composite signals, said apparatus comprising, at least first, second and third input terminals to which said separate first, second and third program signals are respectively applied, first and second output terminals, means connected between said first and second input terminals and said first and second output terminals, respectively, operative to transfer substantially equal amplitude proportions of said first and second program signals without relative phase change to said first and second output terminals, respectively, and means connected between said third input terminal and both said first and second output terminals operative to transfer substantially equal reduced amplitude proportions of said third program signal to both said first and second output terminals and including phase-shifting means operative to provide a differential phase-shift angle between the proportion of said third program signal transferred to said first terminal and the proportion of said third program signal transferred to said second output terminal, which phase-shift angle has a value in the range between 110* and 170* and remains substantially constant over the range of frequencies of said third program signal.
Claim 3
Dependent Claim
58 words
Apparatus in accordance with claim 1 further including a fourth input terminal to which a fourth program signal is applied, and means connected between said fourth input terminal and both said first and second output terminals operative to transfer substantially equal reduced amplitude in-phase proportions of said fourth program signal to both said first and second output terminals.
References Cited (Backward Citations)
US3632886A
Cited
US3646574A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |