| 摘要 |
PURPOSE:To enable encoding of high quality by finding on-frequency-axis data in block units of an audio signal, and switching and quantizing plural code books corresponding to parameters showing features of the respective blocks. CONSTITUTION:A frequency axis conversion processing part 12 provided with a block division part 12a which divides the input speech signal, etc., on the time base into blocks of a specific number of samples, an orthogonal conversion part 12b, a data processing part 12c for finding amplitude information representing the features of a spectrum envelope, etc., converts the speech signal, etc., into the spectrum amplitude data on the frequency axis. A vector quantization part 15 puts a specific number of input data into M-dimensional vectors and thus performs vector quantization. This vector quantization part 15 is equipped with plural kind of code books and switches the code books according to the parameters showing the features of the blocks of the input signal to quantize the signal. Consequently, the vector quantization is performed efficiently corresponding to the characteristics, etc., of the input data. |
