Matsushita Electric Industrial Co., Ltd.

Namio Yamaguti

Keisuke Yamamoto

Minoru Miyata

A ghost signal eliminating system which eliminates a ghost by delaying a video signal through a variable delay line by the delay time of the ghost from the true image and subtracting the delayed video signal from the original video signal. The variable delay line comprises a fine adjusting circuit for fine-adjusting the delay time and a coarse adjusting circuit for coarse-adjusting the delay time, the coarse adjusting circuit being controlled by a detection voltage for a control voltage level and the fine adjusting circuit being controlled by a voltage which is the difference between the control voltage and the detection voltage.

Ghost signal eliminating system

Ghost phenomenon on a screen of a television receiver is removed by supplying an intermediate frequency video signal including a desired signal and a ghost signal to a pair of parallel circuits, each including a synchronous or multiplication detection circuit. The detection axis or reference phase of the first detection circuit differs from the second detection axis or reference phase by an amount equal to the phase difference between the desired signal and the ghost signal. Either the detected video signal in one of the parallel circuits or the intermediate frequency signal applied to one of the parallel circuits is delayed an amount equal to the delay time between the desired signal and ghost signal, and the signals from both circuits are combined in a suitable ratio to cancel the ghost signal.

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Ibaragi, Japan

Namio Yamaguti