| 摘要 |
PURPOSE:To effectively correct the dialect inherent to the reproduction signal of a video tape recorder by providing a waveform shaping circuit removing only a pulse voltage caused at the time of the rise of an input video signal included in a differential wave signal obtained by a differentiating means and adding an original video signal to a shaped differential wave signal. CONSTITUTION:At the time of the rise of the inputted video signal (a), a potential on the input side of a capacitor 2 rises to charge the capacitor 2. The charging current flows through a resistance 3. According to the change in the charging current, voltages Vr on both sides of the resistance 3 increase provisionally as a figure (b) shows, decrease according to a time constant mainly set by the capacitor 2 and the resistance 3, and again return to their original levels. At the time of the fall of the input signal, a potential on the input side of the capacitor 2 falls, the capacitor 2 discharges and a differential voltage never arises in the resistance 3. Accordingly the original video signal and the differential voltage occurring in the resistance 3 are added by an adder 7, whereby the dialect of a video signal (c) is corrected and outputted.
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