| 摘要 |
PROBLEM TO BE SOLVED: To provide a voice processor for performing logarithm compression/expansion wherein various signal processing functions are efficiently added. SOLUTION: In the case ofμLaw compression input, an approximation logarithmic transformation processing is carried out. This processing is provided to carry out the bit inversion of theμLaw compression value, to set MSB as "0", and to calculate an approximationμlog value. Various basic calculation is carried out to the converted approximationμlog value. As for the approximationμlog value, the multiplication processing of a linear value is calculated by operating addition processing, and the division processing of the linear value is calculated by operating substraction processing, and the square processing of the linear value is calculated by operating one bit right shift, the square root of the linear value is calculated by operating one bit left shift, and the double precision of the linear value is calculated by adding "16". Then, the result is outputted so that theμLaw compression output is obtained. COPYRIGHT: (C)2006,JPO&NCIPI
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