CODING AND DECODING METHODS IN ACOUSTIC SIGNAL CONVERSION

摘要

PROBLEM TO BE SOLVED: To obtain a high quantization efficiency. SOLUTION: Input signals are converted into frequency domain coefficients. Prescribed number of coefficients having large values are extracted from the frequency domain coefficients. The extracted coefficient numbers are coded by a coding means 14 and outputted as a sample order index IS. The values of the extracted coefficients are also coded by a coding means 15 and outputted as a sample value index IR. The index IR is decoded by a decoding means 22 in a decoder 21 and frequency domain coefficients are obtained. The inputted index IS is decoded by a decoding means 25 and coefficient numbers are obtained. Then, the decoded coefficients are arranged in the positions of decoded coefficient numbers in the order of larger ones by a means 22. A means 26 reconstructs the frequency domain coefficients and converts them into time domain signals.