Electrical audio signal processing systems and devices – One-way audio signal program distribution – Public address system
Patent
1987-06-26
1990-02-06
Clark, David L.
Electrical audio signal processing systems and devices
One-way audio signal program distribution
Public address system
G10L 702
Patent
active
048993859
ABSTRACT:
Apparatus for encoding speech using a code excited linear predictive (CELP) encoder using a recursive computational unit. In response to a target excitation vector that models a present frame of speech, the computational unit utilizes a finite impulse response linear predictive coding (LPC) filter and an overlapping codebook to determine a candidate excitation vector from the codebook that matches the target excitation vector after searching the entire codebook for the best match. For each candidate excitation vector accessed from the overlapping codebook, only one sample of the accessed vector and one sample of the previously accessed vector must have arithmetic operations performed on them to evaluate the new vector rather than all of the samples as is normal for CELP methods. For increased performance, a stochastically excited linear predictive (SELP) encoder is used in series with the adaptive CELP encoder. The SELP encoder is responsive to the difference between the target excitation vector and the best matched candidate excitation vector to search its own overlapping codebook in a recursive manner to determine a candidate excitation vector that provides the best match. Both of the best matched candidate vectors are used in speech synthesis.
REFERENCES:
patent: 4669120 (1987-05-01), Ono
patent: 4720861 (1988-01-01), Bertrand
Copperi et al., "Vector Quantization and Perceptural Criteria for Low Rate Coding of Speech", IEEE ICASSP 85, pp. 7.6.1-7.6.4.
Gray, "Vector Quantization", IEEE ASSP Magazine, vol. 1, No. 2, 4/84, pp. 4-29.
Schroeder et al., "Code-Excited Linear Prediction (CELP): High-Quality Speech at Very Low Bit Rates", IEEE ICASSP 85, pp. 25.1.1-25.1.4.
Adoul et al., "Fast CELP Coding Based on Algebraic Codes", IEEE ICASSP 87, 4/87, pp. 1957-1960.
Crossman et al., "Multipulse-Excited Channel Vocoder", IEEE ICASSP 87, 4/87, pp. 1926-1929.
Singhal, S. and B. S. Atal, "Improving Performance of Multi-Pulse LPC Coders at Low Bit Rates", Proc. Int. Conf. Acoust., Speech and Sign. Process., San Diego, 1.3.1-1.3.4, 1984.
Atal, B. S. and M. R. Schroeder, "Stochastic Coding of Speech Signals at Very Low Bit Rates", Proc. of ICC, Amsterdam, 1610-1613, 1984.
Trascoso, I. M. and B. S. Atal, "Efficient Procedures for Finding the Optimum Innovation in Stochastic Coders", Proc. Int. Conf. Acoust., Speech and Sign. Process., Tokyo, 2379-2382, 1986.
Atal, B. S., "High-Quality Speech at Low Bit Rates: Multi-Pulse and Stochastically Excited Linear Predictive Coders", Proc. Int. Conf. Acoust., Speech and Sign. Process., Tokyo, 1681-1684, 1986.
Chen, J. H. and Gersho, A., "Real-Time Vector APC Speech Coding at 4800 bps with Adaptive Postfiltering", Proc. Int. Conf. Acoust., Speech and Sign. Process., Dallas, 2185-2188, 1987.
Ketchum Richard H.
Kleijn Willem B.
Krasinski Daniel J.
American Telephone and Telegraph Company
AT&T Bell Laboratories
Clark David L.
Merecki John A.
Moran John C.
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