3917998 is referenced by 49 patents and cites 3 patents.

A new design for a multiple channel repeater having advantages for satellite communications systems is described. The design comprises a pair of complementary N .times. N Butler matrix networks that precede and follow a set of N non-linear amplifying devices. A set of filters follows the output matrix network. The phase shifts produced by the input and output matrices cause a substantial fraction of the intermodulation products to flow to output ports that are tuned to frequencies different than the intermodulation product frequencies. These intermodulation products are therefore attenuated by the output port filters and do not appear as interference. With a portion of the intermodulation products removed from the output signals, the nonlinear amplifiers can operate closer to saturation for a given output carrier-to-intermodulation ratio than a conventional transponder thereby increasing overall DC-to-RF conversion efficiency.

Title
Butler matrix transponder
Application Number
05/412,399
Publication Number
3917998
Application Date
November 2, 1973
Publication Date
November 4, 1975
Inventor
Welti George R
Agent
Sughrue Rothwell Mion Zinn & Macpeak
Assignee
Communications Satellite Corporation
IPC
H04b 01/59
H04B 07/185
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