| 摘要 |
PURPOSE:To eliminate noise before and after the signal rising and falling edges by providing a low pass filter having the properties of rising and falling with a delay with respect to the input pulse and another low pass filter having the properties of rising and falling with a gain with respect to the input pulse. CONSTITUTION:A video signal (a) supplied at an input terminal 3 from which high frequency noise and higher harmonics are removed by a low pass filter (LPF)4, outputted from the LPF4 as signals (b) rising and falling with a delay with respect to the acute rising and falling edges of the video signal (a). Also the noise above + or -L is removed by a limiter 6. The signal (d) is supplied to a substractor 7, and a video signal (e) is obtained from which the noise signal (d) is subtracted so as to be freed of noise. This signal is supplied to the LPF9, outputted from the LPF9 as signal (h) rising and falling with a gain to the edge, the signal (h) is subtracted from the video signal (g) and the amplitude is limited to the level of + or -L at a limiter 11. This signal (j) is supplied to a substractor 12 where the noise signal (j) is subtracted from the original video signal (g) to produce video signal (k) freed of noise.
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