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Digital multi-level multi-phase modulation communication system

  • US 4,347,616 A
  • Filed: 07/30/1980
  • Issued: 08/31/1982
  • Est. Priority Date: 07/31/1979
  • Status: Expired due to Term
First Claim
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1. A digital multi-phase multi-level modulation communication system having a transmitter section and a receiver section, wherein said transmitter section comprises means for multi-phase multi-level modulating a carrier wave with at least four trains of first digital signals each including a first frame signal of a predetermined pattern and for transmitting the modulated carrier wave, and wherein said receiver section comprises means for performing coherent detection and multi-level decision on said modulated carrier wave to provide second digital signals corresponding to said first digital signals, means responsive to at least one of said second digital signals for establishing frame synchronization and providing frame timing, means responsive to said frame timing for extracting second frame signal corresponding to said first frame signal from said second digital signals, and means responsive to said second frame signal and said second digital signals for changing the trains of said second digital signals and the polarities thereof to reproduce said first digital signals from said second digital signals.

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