| 摘要 |
PURPOSE:To eliminate a DC drift component by controlling a holding voltage of an analog accumulator of the most preceding tap of a difference circuit obtaining a difference of a ghost component so as to be a center value of the dynamic range. CONSTITUTION:A vertical synchronizing signal is fed to a gate pulse generator 23, from which a gate pulse corresponding to the end of a ghost detecting section is formed. When the pulse turns on switch circuits 211-22m, an output signal of an analog accumulator 25m is fed sequentially a difference circuit 29m and the output signal of the difference circuits is fed to a weighting circuit 12m. The holding voltage of the accumulator 241 of the most preceding tap is fed to a differential amplifier 41, where the signal is compared with a voltage corresponding to the center of the dynamic range from a voltage source 42. A difference output of the amplifier 41 is fed back to a bias circuit at the input terminal of an amplifier 18, thereby causing a potential of te accumulator 241 to be controlled to be the center value of the dynamic range. |
