| 摘要 |
A subscription television system comprises means for broadcasting a scrambled television signal wherein the NTSC horizontal and vertical synchronization signals are displaced in time from their nominal positions. Each authorized system subscriber is provided with a decoder adapted for restoring the synchronization signals to their nominal positions to enable unscrambling of the broadcast programs for viewing. The synchronizing signals may be time displaced in a static manner or the time displacement may be dynamically varied as a function of time.
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