| 摘要 |
<p>A method of modifying a conventional video signal (62, 64, 70, 72, 74) generates a modified video signal such that a conventional video monitor (78, 82, 86) reproduces a normal picture from the modified video signal, whereas a videotape recording of the modified video signal and subsequent playback thereof produces disturbances in the displayed picture. Predetermined portions (70, 72, 92) of the video signal are identified and copy protection signals (94, 96, 98, 100) are added thereto. An apparatus for processing a conventional video signal to produce an acceptable master recording or transmission signal to display a normal picture on a video monitor and inhibit the display of a normal picture from a subsequent videotape recording thereof includes circuit means (250, 256, 258, 264, 266, 272) for adding chroma bandwidth signals to predetermined signal portions of a conventional video signal, the chroma bandwidth signals having predetermined frequency, wave shape and modulation characteristics whereby upon recording and reproduction by a VCR, the chroma bandwidth signals will produce an interference in the picture.</p> |
