| 摘要 |
To remarkably deteriorate the quality of a reproduced image that is dubbed by a VTR without a deterioration of a reproduced image of a TV receiver. Copy protection signals b and c whose phase is different from that of a burst signal a are placed before and after the burst signal a. This process is performed as ablock composed of several lines to several ten lines every several ten lines toseveral hundred lines as in a portiond. Alternatively, a copy protection signal is placed in alllines so as to improve theeffect of the copy guard as in a portione. When lines in which the copy protection signal is not placed are disposed as in a portion f, the image on the TV receuver becomes stable. When a low band conversion of the VTR is performed for the signal, the duties of the signals b and c increase. Thus, the reproduced image is deteriorated. Since the copy protection signal is placed in a part of the signal a, before the low band conversion is performed, the image is normally displayed on the TV receiver. Since the low band conversion of th VTR is used, the effect of the copy guard for the TV receiver can be separated from that for the VTR.
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