in a code division multiple access communications system , a pn sequence generating device is provided to generate a pn sequence by interleaving of cyclically shifting the symbols of an orthogonal or biorthogonal code in accordance with a pre - defined hopping pattern . a receiver receives simultaneous signals from a plurality of transmitters , where each transmitted signal is spread by a pn sequence generated from the same pre - defined hopping pattern . the receiver is able to differentiate the received signals from each transmitter by varying the amount of interleaving or cyclic shift in each transmitted signal . in the pn sequence generating device , an orthogonal symbol generating portion cyclically shifts mutually orthogonal and periodic orthogonal code sequences , and an orthogonal symbol selector selectively outputs the cyclically shifted orthogonal symbols according to a predetermined pattern .