| 摘要 |
PURPOSE:To prevent an excessive output from being momentarily outputted at the time of inputting a large signal after non-input. CONSTITUTION:An analog input signal is rectified by a full wave rectifier circuit 1 and the peak of a signal obtained by rectifying is held by a peak hold circuit 2. Then, the held signal level and a prescribed reference signal level are compared by a comparator 3. As the result of comparing, when the output of the peak hold circuit 2 is less than the reference signal level, a switch 4 is switched to a reference signal and when the output of the peak hold circuit 2 is over the reference signal level, the switch 4 is switched to the output of the peak hold circuit 2. Thus, the level of the analog input signal is controlled by a VCA circuit 5 in accordance with a signal obtained by switching the switch 4. |
