Patent US4905283A successfully refreshed from Google Patents.
US4905283A
Expired / Lapsed
US
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Surround decoder
Assignee: Sanyo Electric Co Ltd
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Filing: 1989-08-07
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Granted: 1990-02-27
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Expires: 2009-08-07
Abstract
Abstract A surround-decoder comprises terminals to which left and right stereo input signals are applied, a decoder for processing the left and the right stereo input signals to provide left and right stereo output signals, a center output signal and a surround output signal, circuits for detecting the left and the right stereo input signals to be monaural signals, and a switch responsive to an output signal of the detecting circuit for cutting off an output of a surround signal from the decoder.
Inventors
- 👤 Tsutomu Ishikawa
- 👤 Ryuichi Ogawa
- 👤 Masaya Tanno
- 👤 Fumio Tosaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:23
CPC Classifications
H; H04; H04S; H04S5/00; H04S5/02; H04S3/00; H04S3/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
72 words
A surround-decoder comprising: means for providing left and right stereo input signals, decoder means for receiving said left and right stereo input signals to generate left and right stereo output signals, a center output signal and a surround output signal, detectihg means for detecting said left and right stereo input signals to be monaural signals, and means responsive to said detecting means for cutting off said surround signal from said decoder means.
Claim 2
Dependent Claim
72 words
A surround-decoder comprising: means for providing left and right stereo input signals, decoder means for receiving said left and right stereo input signals to generate left and right stereo output signals, a center output signal and a surround output signal, detectihg means for detecting said left and right stereo input signals to be monaural signals, and means responsive to said detecting means for cutting off said surround signal from said decoder means.
Claim 3
Dependent Claim
51 words
A surround-decoder according to claim 1, wherein, said detection means comprises: subtracter means for subtracting said left and right stereo input signals, level detecting means for detecting level of an output signal of said subtracter means, said cutting off means being controlled by an output signal of said level detecting means.
Claim 4
Dependent Claim
40 words
A surround-decoder according to claim 2, wherein, said level detecting means comprises a time constant circuit, and drives said cutting off means to cut off when no output signal of said subtracter means is generated in a predetermined time period.
Claim 5
Dependent Claim
48 words
A surround-decoder according to claim 1, wherein, said left and right stereo input signals are FM stereophonic broadcasting signals comprising a stereo pilot signal of 19 KHz applied from an FM stereo receiver, and said detecting means detects said stereo pilot signal in said FM stereophonic broadcasting signals.
Claim 6
Dependent Claim
43 words
A surround-decoder according to claim 1, wherein said left and right stereo input signals are television multi-sound signals comprising a stereo identifying signal applied from a television multi-sound receiver, and said detection means detects said stereo identifying signal in said television multi-sound signals.
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) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |