| 摘要 |
PURPOSE:To suppress the generation of a thin shadow formed to the right edge side of contour line of a character projected on the surface of a picture tube to provide clear character display by adding a blanking signal with an edge detection signal obtained by differentiating the character signal with respect to time to correct the phase delay and blunting in waveform of the blanking signal itself. CONSTITUTION:An differentiated signal of an emitter output of a character output transistor Qc is applied to the base of a video output transistor Qg as edge detecting signal at blanking. The character output transistor Qc is turned on by the character signal while the differentiated signal of its emitter output goes to a single peak pulse different in polarity for rising and falling the character signal. When the blanking signal delayed in phase by DELTAtau the character signal is applied to emitters of video output transistors Qr, Qg and Qb, conduction at the leading edge is accelerated while the transistors are forced into a nonconducting state at the trailing edge.
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