| 摘要 |
PURPOSE:To reduce the waveform distortion and to make the transmission frequency characteristics flat much more, by adding a passing signal at a high-pass filter side to that of a low-pass filter side at a suitable ratio. CONSTITUTION:A high frequency noise of an input video signal is separated at a high-pass filter 2 having a cut-off frequency f2 and given to a noise cancellation circuit, and a signal cancelled for noise passes through a low-pass filter having a double time constant, cut-off frequency f1 and low-off frequency f2 (f1<f2) and summed with the input video signal passing through a low-pass filter 6 at a suitable ratio. In this way, a high frequency minute signal lost at the noise cancellation is compensated to some degree, the waveform distortion is reduced and the transmission frequency characteristics are made flat much more. |
