| 摘要 |
PROBLEM TO BE SOLVED: To obtain excellent sound quality even at a low bit rate of a voice or music signal. SOLUTION: A 1st orthogonal transformation circuit 150 applies orthogonal transformation to a received signal, a pitch extract circuit 200 uses an output coefficient of the 1st orthogonal transformation circuit to extract a pitch frequency. A harmonic estimate circuit 250 uses the pitch frequency to estimate location of a harmonic in the orthogonal transformation output coefficient and a harmonic quantization circuit 300 quantizes at least one or the output coefficient at the estimated harmonic location and a quantization circuit 400 quantizes the result of eliminating an output of the harmonic quantization circuit 400 from the output coefficient of the 1st orthogonal transformation circuit 150. |
