| 摘要 |
PURPOSE:To prevent generation of a pseudo ghost and automatically erase a ghost signal, by stopping rewriting a data when a data enough for erasing a ghost is obtained in the tap gain memory. CONSTITUTION:A video signal which is obtained from the terminal 1 is provided to the transversal filter 1A. The output of this filter 1A is input to the differentiator A2, the video signal is differentiated, its output is compared with the reference level by the comparator 3, and the output of a prescribed period is stored in the buffer register A4 from the leading edge of the vertical synchronizing signal. And, a signal which has been read out cyclically is provided to one input of the collelator A7. To the other input of this correlator 7A is provided through the digital differentiator A6 a digital data which has waveform-integrated the leading edge part of the vertical synchronizing signal, to which the output of the differentiator A6 is cumulatively added by the correlator 7A, and it is provided to the tap gain memory A8. And, when a data enough for erasing a ghost has been obtained in the memory A8, a control signal is generated from the control circuit 14 which inputs the output of the register A6 through the counter A11, and it is stopped to rewrite a data. |
