A digital data communications method and system combining frequency agility with a frequency-shift-keyed signal to transmit a unique code word representing a plurality of data states. Each code word comprises a plurality of chips, each of which is an integer subportion of the bit time interval in which...http://www.google.de/patents/US4583231?utm_source=gb-gplus-sharePatent US4583231 - Method of, and apparatus for, frequency-hopped frequency-shift-keyed digital data communications
