| 摘要 |
PURPOSE:To encode the drive signal for a speech by using two code books whose code vectors overlap with each other and a composing filter. CONSTITUTION:While a target vector calculation part 11 generates a target vector for vector quantization from a speech signal and a filter coefficient calculation part 1 determines the coefficient of a composing filter from the speech signal, an impulse response calculation part 2 finds an impulse response and a drive signal with an integer pitch period whose code vectors overlap with a code book 3 is interpolated with a drive signal with an integer pitch period to store a drive signal with a non-integer pitch period whose code vectors overlap with a code book 5; and a composite vector is generated by a convolution part 6 with the impulse response and the drive signal with the integer pitch period, a composite vector is generated by a convolution part 7 with the impulse response and the drive signal with the non-integer pitch period, and a drive signal code is searched for by using those composite vectors and target vector. |
