| 摘要 |
PROBLEM TO BE SOLVED: To encode a signal with less deterioration in tone quality with a relatively small operation amount even when bit rate is low and even for not only a wide band sound signal, but also a musical sound. SOLUTION: A spectrum parameter calculation circuit 200 obtains a spectrum parameter from input signals divided into sub-frames by a sub-frame division circuit 120 to quantize it. A division circuit 410 divides subtraction result of a subtracter 235 into plural pieces of sub-bands, and an adaptive code book circuit 300 obtains pitch information in at least one among the subbands to obtain a pitch estimate signal, and a discrimination circuit 420 performs discrimination of pitch estimate in at least one among the subbands by using the pitch information, and synthetic circuit 430 synthesizes the pitch estimate signal. A subtraction circuit 236 subtracts the pitch estimate signal from the subtraction result of the subtracter 235 to obtain a sound source signal, and a sound source quantization circuit 350 quantizes the sound source signal by referring to a sound source code book 355. |
