SHORT TIME DELAY CONVERSION ENCODER AND DECODER FOR HIGH QUALITY AUDIO SIGNAL

摘要

PROBLEM TO BE SOLVED: To code a high quality music at a low bit rate (128 kb/s) by using an analysis.synthesis window versus adaptive conversion coefficient quantization processing and adaptive bit assignment. SOLUTION: A broad band audio signal is sampled and quantized (101) into sample blocks of a time region and each sample block is modulated by an analysis window 103 and a spectral component in the frequency region is generated in response to the sample blocks in the time region weighted by an arnalysis window. Each conversion coefficient is ununiformly quantized (108) with the conversion coder conducting adaptive bit assignment 106 and the coefficients are assembled (110) into a digital output with a format 109 suitable for the storage or the transmission. The decoder generates the time region signal sample block in response to the spectrum of the frequency region by are element with a free characteristic with respect to elements of the time region spectrum in the encoder and decoded by a synthesis window 115 and a duplicate sum element 116.