PURPOSE: To improve the information compression efficiency by storing the result of collation at least by one frame.
CONSTITUTION: Upon the receipt of spectrum information 106, an element 431 of each code vector is read from a code book 401 of a collation section 400, and a distance calculation section 402 calculates the distance of vectors 106. In the case of retrieving all numbers, a distance 403 of all code vectors in the code book is calculated and the result is fed to a minimum value detection section 404, and a pointer 405 of a code vector (nearest vector) whose value 403 is minimized is outputted. Thus, when the input vector is expressed by plural code vectors, it is not required to send part of the pointer of the code vector. In this case, since quantization distortion is hardly increased, the information compression efficiency is enhanced.
YAMAZAKI KATSUYA
ICHIKAWA HIROSHI