CODING AND DECODING DEVICE ROBUST AGAINST RANDOM ERROR, NOT REQUIRING ADDITIONAL BIT FOR ERROR DETECTION AND CORRECTION

摘要

PURPOSE: A coding and decoding device robust against a random error is provided to convert a coded bit string to be of a robust type against errors before transmitting or recovering the bit string, thereby minimizing fading of tone quality. CONSTITUTION: A coding unit(200) performs vector quantization for sampled voice signals by referring to a vector quantization code book(202). A vector quantization code ordering unit(208) rearranges the sequence of vector quantization codewords, such that the codewords having high similarity outputted from the coding unit(200) are adjacent to each other. A mapping unit maps a created sequential binary code to a gray code. An inverse mapping unit inversely maps the gray code to the original sequential binary code. A vector quantization code inverse ordering unit(210) recovers the sequence of the vector quantization codewords rearranged such that the codewords having high similarity outputted from the inverse mapping unit are adjacent to each other. A decoding unit(204) performs inverse vector quantization for the resulting sequential binary code by referring to the vector quantization code book(202), to recover the sampled voice signals.