| 摘要 |
PURPOSE:To cancel the noise completely by applying the output of the noise canceller to the connection between the feedback element and the CR circuit. CONSTITUTION:The output of the CR circuit comprising resistance R1 and R2 connected in series plus capacitor C1 is applied to amplifier circuit Amp, and the output is fed back to connection N2 of R1 and R1. Thus, an active filter is constituted. On the other hand, the reference voltage of reference voltage generation circuit 1 is compared with the input signal to be given to input part 2 through comparator 3 in order to detect the noise exceeding the reference voltage. Thus, the noise cancel signal is generated form gate circuit 4 to be applied to node N2. The noise pulse applied to input terminal N1 causes a time delay at node N2 via the active filter and causes another delay at output terminal N3. Accordingly, the noise part which was not erased at the rise and fall time of the noise pulse can be reduced so much as to be ignored by applying the cancel signal to node N2 where the intermediate signal delay is caused. |
