US4184047A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio signal processing system
Assignee: Individual
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Filing: 1977-06-22
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Granted: 1980-01-15
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Expires: 1997-06-22
Abstract
Abstract An audio signal processing system for enhancing audio signals such as music by providing reverberation, generation of stereophonic or quadraphonic effects, chorusing, flanging, pitch change, vibrato and various combinations of these effects. An audio signal is passed through a compressor, to increase its signal-to-noise ratio,and then through a delay circuit. The delayed audio signal is passed through an expandor to restore the original input level. Preferably, before being applied to the compressor the audio signal passes through a pre-emphasis circuit and, after passing through the expandor, through a de-emphasis circuit, thereby emphasizing desired frequencies. In some embodiments, the processed output signal is blended with the received audio signal to provide a blended audio signal, and in some embodiments the processed audio signal is fed back to the system input for recirculation, providing reverberation. The delay circuit is preferably an analog shift register.
Inventors
- 👤 Robert H. Langford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:51
CPC Classifications
G; G10; G10H; G10H1/00; G10H1/0091; G10H1/02; G10H1/06; G10H2210/00; G10H2210/155; G10H2210/195; G10H2210/201; G10H2210/235; G10H2210/245; G10H2210/251; G10H2210/265; G10H2210/281; G10H2210/295
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
95 words
An audio signal processing system comprising: input means for receiving an audio signal; a compressor coupled to said input means for compressing the received audio signal; time delay means coupled to said compressor for delaying the compressed audio signal; an expandor coupled to said time delay means for expanding the delayed audio signal; output means for providing a processed output signal from said system; and signal blending means coupled to said time delay means and to said compressor for blending the delayed audio signal with the compressed audio signal to provide a blended audio signal.
Claim 2
Dependent Claim
95 words
An audio signal processing system comprising: input means for receiving an audio signal; a compressor coupled to said input means for compressing the received audio signal; time delay means coupled to said compressor for delaying the compressed audio signal; an expandor coupled to said time delay means for expanding the delayed audio signal; output means for providing a processed output signal from said system; and signal blending means coupled to said time delay means and to said compressor for blending the delayed audio signal with the compressed audio signal to provide a blended audio signal.
Claim 3
Dependent Claim
33 words
An audio signal processing system as claimed in claim 1 further comprising recirculation means for applying a portion of the expanded audio signal to the compressor for recirculation with the received audio signal.
Claim 4
Dependent Claim
46 words
An audio signal processing system as claimed in claim 2 further comprising a pre-emphasis circuit coupling said input means to said compressor for emphasizing selected signal frequencies and a de-emphasis circuit coupling said expandor to said output means for restoring substantially the original signal power distribution.
Claim 5
Dependent Claim
61 words
An audio signal processing system as claimed in claim 3 further comprising a first low pass filter coupling said input means to said compressor for filtering out signals of a frequency above a first selected frequency, and a second low pass filter coupling said expandor to said output means for filtering out signals of a frequency above a second selected frequency.
Claim 6
Dependent Claim
61 words
An audio signal processing system as claimed in claim 2 further comprising a first low pass filter coupling said input means to said compressor for filtering out signals of a frequency above a first selected frequency, and a second low pass filter coupling said expandor to said output means for filtering out signals of a frequency above a second selected frequency.
Claim 7
Dependent Claim
61 words
An audio signal processing system as claimed in claim 1 further comprising a first low pass filter coupling said input means to said compressor for filtering out signals of a frequency above a first selected frequency, and a second low pass filter coupling said expandor to said output means for filtering out signals of a frequency above a second selected frequency.
Claim 8
Dependent Claim
46 words
An audio signal processing system as claimed in claim 1 further comprising a pre-emphasis circuit coupling said input means to said compressor for emphasizing selected signal frequencies and a de-emphasis circuit coupling said expandor to said output means for restoring substantially the original signal power distribution.
Claim 9
Dependent Claim
61 words
An audio signal processing system as claimed in claim 7 further comprising a first low pass filter coupling said input means to said compressor for filtering out signals of a frequency above a first selected frequency, and a second low pass filter coupling said expandor to said output means for filtering out signals of a frequency above a second selected frequency.
Claim 10
Dependent Claim
60 words
An audio signal processing system as claimed in claim 1 further comprising: second time delay means coupled to said signal blending means for further delaying the blended audio signal; and second signal blending means coupling said first blending means and said second time delay means with said expandor for blending the blended audio signal with the further delayed audio signal.
Claim 11
Dependent Claim
27 words
An audio signal processing system as claimed in claim 1 further comprising second signal blending means for blending the expanded audio signal with the received audio signal.
Claim 12
Dependent Claim
54 words
An audio signal processing system as claimed in claim 10 in which said output means is coupled to said expandor to provide the expanded audio signal as the processed output signal; said system further comprising second output means connected to said second signal blending means for providing a blended output signal from said system.
Claim 13
Dependent Claim
34 words
An audio signal processing system as claimed in claim 11 further comprising third output means coupled to said input means for providing the received audio signal as a third output signal from said system.
References Cited (Backward Citations)
US3969680A
Cited
US3959597A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-14 | 1983-07-16 | 1984-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-14 | 1987-07-16 | 1988-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-14 | 1991-07-16 | 1992-01-15 | $7700.00 | Window Closed / Lapsed |