| 摘要 |
PROBLEM TO BE SOLVED: To realize high quality coding of sound by enabling a large number of coding bits to be allotted to the number of pulse position candidates of a string of pulses used as drive signal. SOLUTION: An input sound signal to an input terminal 101 is given to an LPC synthesizing part 104 via an LPC analyzing part 102 and an LPC quantizing part 103, these forming a synthesized filter, and the sound signal is coded by being expressed by a quantized LPC coefficient, showing the characteristics of the synthesized filter and by a drive signal for driving the synthesized filter. Pulse position candidates are selected from integer pulse positions and non-integer pulse positions stored in a pulse position code register 110 by a pulse position selecting part 111 in a pulse sound source part 105A, integer position pulses set up in positions of sample points of the drive signal and non-integer position pulses set up in middle positions between the sample points are generated by an integer pulse generating part 112 and a non-integer pulse generating part 113, respectively, and a string of pulses providing the basis for the drive signal are generated by unifying them. |
