Satellite multiple access system with distortion cancellation and compression compensation
First Claim
1. A method for eliminating service outages from various causes, including physical blockage, multipath fading and electronic interference, in the transmission of at least two radio broadcast signals having substantially the same content to a plurality of mobile receivers for said signals comprising:
- broadcasting a first substantially undelayed radio broadcast signal to said plurality of mobile receivers;
after a time delay of desired length following the broadcast of said first radio broadcast signal, broadcasting a second radio broadcast signal containing substantially the same program content as said first radio broadcast signal to said plurality of mobile receivers;
storing, in each of said mobile receivers, said first, substantially undelayed radio broadcast signal for a time period substantially the same as the time of said time delay;
outputting from each of said plurality of mobile receivers, the program contents of said first and said second radio broadcast signals by combining said first and said second radio broadcast signals for output or by selecting for output, in correct time-ordered progression, portions of said first radio broadcast signal and portions of said second radio broadcast signal; and
transmitting, with said radio broadcast signals, a noise-cancelling signal that is opposite in phase to inter-modulation noise in said radio broadcast signal but is the same as said radio broadcast signal in all other respects.
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Accused Products
Abstract
A multicarrier satellite communications system includes one or more satellites and one or more transmitters at generally terrestrial locations that transmit a plurality of signal carriers to the satellites which contain non-linear signal repeaters that produce inter-modulation noise or signal compression in the signal carriers. The noise is minimized/cancelled by adding to the signal carriers, at the generally terrestrial locations where the transmitters are located, noise-cancelling or signal compression-correcting signals.
76 Citations
27 Claims
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1. A method for eliminating service outages from various causes, including physical blockage, multipath fading and electronic interference, in the transmission of at least two radio broadcast signals having substantially the same content to a plurality of mobile receivers for said signals comprising:
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broadcasting a first substantially undelayed radio broadcast signal to said plurality of mobile receivers; after a time delay of desired length following the broadcast of said first radio broadcast signal, broadcasting a second radio broadcast signal containing substantially the same program content as said first radio broadcast signal to said plurality of mobile receivers; storing, in each of said mobile receivers, said first, substantially undelayed radio broadcast signal for a time period substantially the same as the time of said time delay; outputting from each of said plurality of mobile receivers, the program contents of said first and said second radio broadcast signals by combining said first and said second radio broadcast signals for output or by selecting for output, in correct time-ordered progression, portions of said first radio broadcast signal and portions of said second radio broadcast signal; and transmitting, with said radio broadcast signals, a noise-cancelling signal that is opposite in phase to inter-modulation noise in said radio broadcast signal but is the same as said radio broadcast signal in all other respects. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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- 16. A multicarrier satellite communications system comprises at least one satellite and at least one transmitter at a generally terrestrial location that transmits a plurality of synchronous CDMA composite signal carriers to said at least one satellite, said signal carriers generating signal compression in said at least one satellite, said system also including means for generating and for adding to said signal carriers, at said terrestrial location, compression compensation signals that minimize said signal compression in said at least one satellite.
Specification