| 摘要 |
PURPOSE:To suppress the overshoot by inputting a signal proportional to the absolute of an input to a smoothing circuit when the result of division overflows in a digital compression circuit in which the compression is applied by dividing an input signal by a signal being made into absolute value and applied with smoothing processing to an output of a low pass filter. CONSTITUTION:A signal subject to pulse code modulation enters a terminal 1, divided by an output of a low pass filter 29 by a divider 2 and the result is outputed to an output terminal 4. The said output is detected and smoothed by an absolute value circuit 10 and the low pass filter 29 and fed back to the divider 2. Thes the amplitude compression is applied. If the input signal is increased suddenly, since the output of the low pass filter 29 is small, the divider might cause an overflow. In detecting the overflow by an overflow detection circuit 5, a switch 34 is changed over to give a signal proportional to the absolute value of the input to a register 9. As a result, the output of the low pass filter 29 is proportional to the input signal to eliminate the overflow. When the overflow is eliminated, the switch 34 is thrown to the original position. |
