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Abstract

A video tape on which a series of video signal to be reproduced as a series of visible images by a video signal reproducing apparatus is recorded together with disturbing signals for disturbing a video tape-recorder in copying the series of video signals so as to be normally reproduced by a video signal reproducing apparatus. Each of the video signals is accompanying by a back porch and a horizontal synchronous signal and the series of video signals is divided into a plurality of subseries of video signals with vertical retrace-sweep blanking periods interposed and the horizontal synchronous signals being contained also in the vertical retrace-sweep blanking periods. The disturbing signals include a series of first pulse signals inserted just after the horizontal synchronous signals and a series of second pulse signals inserted in a period after the horizontal synchronous signals wherein the period corresponds to the time of the back porch.

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First Claim