| 摘要 |
A speech signal decoding device is provided with an adaptive codebook decoding unit (102), a fixed codebook decoding unit (103), a ratio calculation unit (107), a determination unit (109), and an attenuator (110). The adaptive codebook decoding unit (102) generates an adaptive codebook vector using adaptive codebook codes for a code signal coded by the CELP method. The fixed codebook decoding unit (103) generates a fixed codebook vector using fixed codebook codes for the code signal. The ratio calculation unit (107) calculates the ratio of amplitudes or the ratio of energies between the adaptive codebook vector and the fixed codebook vector. The determination unit (109) determines whether or not the ratio of amplitudes or the ratio of energies exceeds a prescribed threshold. When it is determined that the ratio of amplitudes or the ratio of energies exceeds a prescribed threshold, the attenuator (110) attenuates an excitation signal defined by adding the adaptive codebook vector and the fixed codebook vector. |
