| 摘要 |
PURPOSE:To obtain a maximum luminance of an accurate video signal by giving a signal switching the state of a buffer and the state of maximum value detection to two multiplexers. CONSTITUTION:When the maximum value detection mode is selected by a video/peak switching signal generating means 113, a capacitor 103 is connected to the emitter load of a transistor (TR) 101 by a multiplexer 106 only in the timing of an effective pattern by an effective pattern signal generated by an effective pattern signal generating means 112. The potential across the capacitor 103 is kept to a potential representing the maximum brightness of an inverted input video signal by a diode located across the base and emitter of the TR 101. The voltage is given to a buffer amplifier 104 at a high impedance and outputted at a low impedance and fed to the base of an emitter follower composed of a TR 107 with different polarity to that of a 1st TR 101 and outputted from the emitter with a low impedance. Thus, an accurate maximum value is obtained.
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