Coded data generation or conversion – Digital code to digital code converters – Adaptive coding
Patent
1993-09-08
1995-01-10
Young, Brian K.
Coded data generation or conversion
Digital code to digital code converters
Adaptive coding
381 37, H03M 700
Patent
active
053811437
ABSTRACT:
A digital signal processing system comprising a compressor, an expander and a scale-down circuit. The compressor includes non-block frequency analyzer that frequency analyzes the digital input digital signal, without dividing it into block, to provide a frequency range signal in each of plural frequency ranges. A block frequency analyzer divides the frequency range signals into blocks and performs a block frequency analysis of each block of the frequency range signals to provide a block of spectral coefficients. A quantizer quantizes the block of spectral coefficients from the block frequency analyzer to provide a block of a compressed signal. The expander includes a block frequency synthesizer that performs a block frequency synthesis to transform, from the frequency domain to the time domain, the spectral coefficients in each of the frequency ranges in each block of the compressed signal to provide, in each of the frequency ranges, a block of a reproduced frequency range signal. A non-block frequency synthesizer synthesizes the reproduced frequency range signals, without dividing them into blocks, to provide the digital output signal. Finally, the system includes a scale-down circuit that scales down values in the block frequency analysis performed by the block frequency analyzer or the block frequency synthesis performed by the block frequency synthesizer. The scale-down circuit operates to cause the noise levels resulting from scaling down the values to be different in each of the frequency ranges.
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Abe Miki
Akagiri Kenzo
Shimoyoshi Osamu
Watanabe Takahiro
Sony Corporation
Young Brian K.
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