| 摘要 |
PURPOSE:To reduce processing and time for deciding the code of excitation source information contributed for a voiced sound rather than conventional processing and time and to less reduce the number of bits required for the excitation source information contributed for the voiced sound rather than the conventional device. CONSTITUTION:In the code excitation linear predictive encoding device, a long- term analyzer 12 obtain a frame lag L of an input voice signal at every frame period, and an excitation source evaluation circuit 13 searches an adaptive code book 14 from among the adaptive excitation code vectors before and behind the prescribed number with an adaptive excitation code vector corresponding to the frame lag L as a center in the case of searching the adaptive code book 14. In this case, when the encoded voice signal contains both the frame lag and a sub frame corrected lag DELTAL as the information of time difference between the optimum adaptive excitation code vector obtained as the result of search and the adaptive excitation code vector corresponding to the frame lag, the efficiency of compression can be improved in comparison with the conventional device. |
