Patent ID: 6587984
Filing Date: 2003-07-01
Classification: H03M

Abstract:
A digital audio signal distortion correcting device comprising:storage means (2) for storing a digital audio signal converted to code by an analog/digital converter; occurrence frequency detecting means (3) for extracting a plurality of samples from said digital audio signal stored in said storage means (2) and counting an occurrence frequency of said samples for every code expressing a quantization level of the samples to obtain a level distribution; normalizing means (34) for generating, by applying a low-pass filtering process on the original level distribution detected by said occurrence frequency detecting means (3), an ideal level distribution approximating an ideal case where said analog/digital converter has no error, dividing said original level distribution by said ideal level distribution, and setting the division result thereof as a normalized level distribution; conversion table calculating means (35) for calculating, based on said normalized level distribution, a conversion table in which data bit lengths are extended to make a correction with respect to a conversion error of said analog/digital converter for all of said quantization levels of said digital audio signal; and data substituting means (36) for substituting said quantization level of said digital audio signal with level data according to said conversion table for output.