| 摘要 |
PURPOSE:To detect accurately the peak value of a signal even when a DC component is superposed and also to compare it with a reference value by coupling a signal input with a peak value detecting circuit on a DC basis and inputting the reference voltage. CONSTITUTION:The input signal is coupled with the base of a transistor (TR) Q1 on a DC basis, and the emitter of the TRQ1 is connected to the emitter of a TRQ2 through a resistance R1 and a capacitor C1. The reference voltage Vref is applied to the base of the TRQ2. Therefore, the peak value of the input signal has its peak value detected by the resistance R1 and capacitor C1 and a voltage Vp proportional to the difference between the peak value and reference value is outputted to the emitter of a TRQ3. Consequently, not a signal amplitude, but the real peak value is detected and also compared with the reference value simultaneously. |
