| 摘要 |
PURPOSE:To reduce granular noise and inclined overload noise effectively by compressing change of amplitude of pulse modulated analog input signals by a logarithmic compander. CONSTITUTION:Amplitude of analog input signals Ain is compressed by a loga rithmic companding circuit 11, and converted to analog signals f (Ain) and supplied to a pulse modulating circuit 1. Then, the difference DELTAn obtained from quantized value of the signals f (Ain) is transmitted to a demodulating circuit 2. In the demodulating circuit 2, analog signals f (Aout) logarithmic compressed from the difference DELTAn are obtained by operation reverse to the modulating circuit 1. Amplitude of the signals (f) (Aout) is expanded by an inverse logarith mic companding circuit 13, and demodulated output signals Aout of nearly the same amplitude with the input signals Ain are obtained. Thus, granular noise and inclined overload noise can be reduced effectively. |
