Satellite video multiplexing communications system
First Claim
1. In combination in a video transmission system for communicating two video programs via a single communications channel, a transmitter including means for supplying first and second television signals each including successive lines of video information separated by horizontal synchronizing pulse periods, first and second storage means for storing successive lines of said first television signal, third and fourth storage means for storing successive lines of said second television signal, first demultiplexing means for loading said first and second television signals into said first and second, and said third and fourth storage means therefor, respectively, means for generating a digital synchronizing word, and first multiplexing means for cyclically supplying said synchronizing word, one line of said first television signal read out from an alternating one of said first and second storage means, and one line of said second television signal read out from an alternating one of said third and fourth storage means.
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Accused Products
Abstract
A video multiplexing communications system for distributing two distinct video programs via a single satellite channel utilizes time division principles, transmitting alternating lines of video information for the two programs by a single frequency modulated carrier to increase FM carrier-to-noise, thereby also maintaining each video program signal-to-noise ratio above FM detection threshold. The alternating lines are compacted in time and occupy a substantial portion of the synchronizing pulse period of the video lines; one line is partially repeated to reduce spurious system transient responses upon inter-program line switching; and amplitude expansion/reduction may be employed to maintain a large FM carrier deviation.
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Citations
26 Claims
- 1. In combination in a video transmission system for communicating two video programs via a single communications channel, a transmitter including means for supplying first and second television signals each including successive lines of video information separated by horizontal synchronizing pulse periods, first and second storage means for storing successive lines of said first television signal, third and fourth storage means for storing successive lines of said second television signal, first demultiplexing means for loading said first and second television signals into said first and second, and said third and fourth storage means therefor, respectively, means for generating a digital synchronizing word, and first multiplexing means for cyclically supplying said synchronizing word, one line of said first television signal read out from an alternating one of said first and second storage means, and one line of said second television signal read out from an alternating one of said third and fourth storage means.
- 23. In combination in multiplexed television signal receiver apparatus for receiving a radiated wave comprising a time division multiplexed digital message, one video line of a first television signal and one line of a second television signal, said receiver apparatus including first and second storage means for storing successive lines of video information of said first television signal, third and fourth storage means for storing successive lines of video information of said second television program, receiver timing means including sync recovery means for detecting said digital synchronizing word, demultiplexing means connected and responsive to output signals from said timing means for storing received first and second signal video information into said first through fourth storage means and multiplexing means connected and responsive to output signals from said timing means for serially converging the stored contents of said first and second storage means to reconstruct said first television signal video information and for serially converging the stored contents of said third and fourth storage means to reconstruct said second television signal video information.
Specification