A demodulator unit is disclosed for spread spectrum apparatus utilized in a cellular mobile communication system. The cellular mobile communication system includes a plurality of fixed base stations connected with a central processor so that calls originating in any cell can terminate in any other cell. Each mobile unit has a unique set of time-frequency coded waveforms that are used for both transmission and reception. Message modulation is accomplished by digitizing the speech and encoding the resulting binary sequences into the set of waveforms available to the user, while detection is accomplished by the demodulator unit in which the phases of each received waveform are compared with those of the preceding waveform. The demodulator unit includes a tapped delay line which can have mixers before and after the delay line and can be a narrowband unit with delays and mixers.