| 摘要 |
PURPOSE:To reduce the waveform distortions without deteriorating the effect of the S/N improvement by obtaining the noise signals. CONSTITUTION:A high band pass filter 9 deletes both DC and low frequency components and extracts only the noise component that appears at random. If a signal (a) is supplied to a point (a), a point (b), i.e., the output of a feedback type Y comb-shaped filter and a point (c), i.e., the output of a vertical high band pass filter have waveforms (b) and (c) respectively. Then the waveform of the point (c) is transmitted through the filter 9 and a waveform (f) is obtained at a point (f). This waveform (f) contains substantially no DC component and it can be judged that the waveform (f) contains virtually the noise component only excepting for the spike-shaped signal obtained at a part where the signal has a large change. Furthermore the output of a limiter 7, i.e., a waveform (e) is obtained at a point (d) in case the signal obtained at the point (f) is transmitted through the limiter 7. The waveform of the point (d) contains virtually the noise component only and no low frequency component that causes the waveform distortions.
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