Scrambling system for television sound signals
First Claim
1. In a television system having a transmitter, a receiver and a communication channel for processing video signals, an audio-scrambler apparatus for a continuous audio signal to be transmitted through said television system comprising:
- means for dividing said continuous audio signal into consecutive audio segments of a predetermined length;
first means for cylically rotating each of said divided segments in accordance with a pseudo-random pattern to derive rotated audio segments;
second means for subdividing said rotated segments into subsegments and for compressing each of said subsegments down to the length of a video line of said television system;
scrambling means responsive to said compressed subsegments and to the video signals of said television system for cyclically rotating each of said compressed subsegments in time concurrence with the vertical blanking pulse of said television system and for cyclically rotating each video signal in time concurrence with the video lines, in accordance with another pseudo-random pattern to derive rotated compressed audio signals and rotated video signals; and
third means responsive to the vertical blanking pulse of said television system for inserting each of said rotated compressed audio signals as a video line into a corresponding one of the vertical blanking spaces separating the active video lines of said television system and for generating a composite rotated audio and video signal to be transmitted.
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Accused Products
Abstract
An audio scrambler operates on segments of audio divided from a continuous audio signal to rotate head-to-tail the string of information contained in the segment by an amount which is at pseudo-random between the successive segments. When the segments are compressed to video format, the scrambled compressed audio signals are inserted into an unused line of the vertical blanking space of a television system for transmission with the video signals. The inserted audio is combined with decoy signals, also in the vertical blanking space to increase security of transmission. Concurrent scrambling of compressed audio signals and video signals is provided.
189 Citations
4 Claims
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1. In a television system having a transmitter, a receiver and a communication channel for processing video signals, an audio-scrambler apparatus for a continuous audio signal to be transmitted through said television system comprising:
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means for dividing said continuous audio signal into consecutive audio segments of a predetermined length; first means for cylically rotating each of said divided segments in accordance with a pseudo-random pattern to derive rotated audio segments;
second means for subdividing said rotated segments into subsegments and for compressing each of said subsegments down to the length of a video line of said television system;scrambling means responsive to said compressed subsegments and to the video signals of said television system for cyclically rotating each of said compressed subsegments in time concurrence with the vertical blanking pulse of said television system and for cyclically rotating each video signal in time concurrence with the video lines, in accordance with another pseudo-random pattern to derive rotated compressed audio signals and rotated video signals; and third means responsive to the vertical blanking pulse of said television system for inserting each of said rotated compressed audio signals as a video line into a corresponding one of the vertical blanking spaces separating the active video lines of said television system and for generating a composite rotated audio and video signal to be transmitted. - View Dependent Claims (2, 3, 4)
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Specification