Electrical audio signal processing systems and devices – One-way audio signal program distribution – Public address system
Patent
1989-04-18
1991-08-20
Harkcom, Gary V.
Electrical audio signal processing systems and devices
One-way audio signal program distribution
Public address system
381 29, 381 30, 381 36, 381 37, G10L 706, G10L 302
Patent
active
050420690
ABSTRACT:
Apparatus and method for reconstructing non-quantized adaptively transformed voice signals are shown to include noise shaping wherein the spectral envelope is scaled prior to generating bit allocation and energy substitution which is achieved after dequantization by generating the spectral envelope information for each block of transform coefficients based upon side information, generating transform coefficients which correspond to transform coefficients which were not de-quantized and for substituting the generated transform coefficients into said blocks; and transforming said blocks of de-quantized transform coefficients and generated transform coefficients from said transform domain into said time domain. Generating transform coefficients is accomplished by determining from the bit allocation signal to which of the transform coefficients no bits were allocated, retrieving the spectral envelope information corresponding to the transform coefficients to which no bits were allocated, providing a positive or negative sign to each item of spectral envelope information so retrieved, scaling the magnitude of each item of spectral envelope information so retrieved, and by substituting each item of spectral envelope information so retrieved into the block of de-quantized transform coefficients after each item has been given a sign and scaled.
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Chhatwal Harprit
Wilson Philip J.
Harkcom Gary V.
Knepper David D.
Pacific Communications Sciences, Inc.
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