Data modem apparatus

Claim 1

Phase coding logic means for use in an eight-phase modulating and transmitting system comprising, in combination: first, second, and third binary logic means for providing binary data indications of first, second, and third channels, respectively; first exclusive NOR logic means connected to said first and second data sources and providing an exclusive NOR output indicative of data received from said first and second sources; first, second, third, and fourth pulse timing source means each indicative of different phase relationships; first AND gate means connected to receive the output from said first exclusive NOR means and to receive said third pulse timing signal and for providing a first output; second AND gate means connected to said second binary logic means for receiving signals therefrom and further connected to said fourth pulse timing source means for receiving signals therefrom and for providing a second output; second exclusive NOR means connected to the output of saiD first exclusive NOR means for exclusive NORing the output therefrom with an output received from said third data source means, said second inclusive NOR means providing an output indicative of the received signals; third AND gate means connected to said second pulse timing source means for receiving timing signals therefrom and connected to said second exclusive NOR means for receiving signals therefrom, said third AND gate means providing a third output; and OR gate means connected for receiving outputs from said first, second, and third AND gate means and from said first pulse timing source means and for providing a logical coded output thereof.