An apparatus for synchronizing the system clocks of wireless devices in a digital
communications system is presented. A digital phase-locked loop is employed. The
phase-locked loop may include a counter which is incremented by a local device
system clock and latched by a frame synchronization marker received from a remote
device, whereby the counter output comprises a feed forward signal. The phase-locked
loop may alternatively include a counter that reflects the level of data stored
in receive and/or transmit FIFO buffers. The loop output signal controls the frequency
of the system clock oscillator.
