| 摘要 |
PURPOSE:To eliminate noise independently of its invaded position while keeping the waveform of an input signal by providing a charge/discharge circuit applying charging or discharging momentarily in response to the input digital signal and applying the other operation in a prescribed time constant and a charge/ discharge circuit compensating the duty of the signal. CONSTITUTION:A charge/discharge signal Sa in response to the input digital signal S1 is formed by the 1st charge/discharge circuit (Q1, R3, C2) and the signal is compared with a reference signal TH by a comparator circuit 5 to obtain a digital signal from which a noise NSL is eliminated. In this case, the discharging being one of the charging/discharging operations of the charge/ discharge circuit (Q1, R3, C2) is applied momentarily, the other operation (charging) is executed in a prescribed time constant so that the noise is eliminated independently of the invaded position of the noise NSL while the preceding state is affected by the noise when the other operation (charging) is executed. Then the 2nd charge/discharge circuit (Q2, R6, C3) and a comparator circuit 6 retard the leading or trailing edge of the digital signal after the elimination of noise to obtain an output digital signal S3 having the equal duty to that of the input digital signal S1. |
