| 摘要 |
PURPOSE:To eliminate the need for a coil and to easily execute an IC operation by a constituting of a variable gain circuit to input an image signal and output an signal inverted by 180 deg. with the phase, the first and second amplifying circuits to convert a difference voltage between two inputs to an electric current and an active filter constituted of a capacitor. CONSTITUTION:In a picture quality adjusting circuit 14 composed of a variable gain circuit 19, amplifying circuits 20 and 21 and capacitors C1 and C2, a video signal is inputted to circuits 19 and 20, the circuit 19 outputs a 180 deg. phased inverted signal and circuits 20 and 21 converts the difference voltage of the input to an electric current. At such a time, the circuit 14 is operated to the signal inputted from the amplifying circuit 20 as a secondary LPF and operated to the signal inputted from the circuit 19 as a secondary HPF. For such a reason, to the output of the circuit 14, the low frequency signal of a video signal inputted from the amplifying circuit 20 and the high frequency signal to phase-invert the video signal inputted from the circuit 19 by 180 deg. are added and outputted. At such a time, by controlling the gain of the circuit 19, the high frequency level of the output signal of the circuit 14 is controlled.
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