a method and apparatus for phase - coherently demodulating a multipath - impaired time division multiple access qpsk data timeslot is disclosed . a quadrature separator generates multipath - impaired intermediate signals which , during a predetermined synchronizing sequence for the timeslot , are applied to a pair of synchronizing correlators to generate quadrature multipath profiles . these profiles then are used to modify subsequently received qpsk timeslot signals at the separator outputs to coherently construct multipath compensated i and q channel data .