| 摘要 |
PURPOSE: To prevent buffer overflow and underflow by increasing or reducing the truncation of a digital sample signal according to the increment or decrement of fullness respectively. CONSTITUTION: As the fullness of a transmitting buffer 36 increases more, the truncation of an input to a digital compressing filter 28 is increased more, and an average encoder output bit rate is reduced below the bit rate of the channel so as to reduce the fullness of the buffer 36. Also, when the fullness of the buffer 36 reduces below a prescribed threshold level, a means which changes the operation of a variable word length encoder 30 is given so that it may operate with out of range(OOR) operation mode independently of the range of a supplied input signal. Thus, the bit rate to the buffer 36 is increased. Thereby, the overflow of the buffer 36 is eliminated and also the underflow of the buffer 36 is avoided. |
