a communication system and method for continuous phase modulation providing for transmission of a phase - modulated carrier having a phaseform representative of concurrently transmitted symbols . the phaseform of the phase - modulated signal is a sum of shift bi - orthogonal functions , each term in that sum being weighted by one of the overlapping symbols . the communication system and method provide full - response demodulation for the recovery of a particular symbol from among the concurrently transmitted symbols by selecting a receiving filter function shift bi - orthogonal to the transmitter filter function corresponding to the particular symbol . the communication system and method then provide for nulling , by integration over a time interval during which the particular symbol is transmitted , those transmitter filter functions that do not correspond to the particular symbol . this results in the separation of the particular symbol from the other concurrently transmitted symbols .