A wireless communication system (10) uses a phase detector (28) having a
first pair of flip-flops (50, 56) for detecting the phase difference
between an input frequency and a reference frequency. The first pair of
flip-flops control current sources (66, 70) in the charge pump of the
phase detector to modulate the error signal. A second pair of flip-flops
(52, 58) detect when the input frequency is more than 2.pi. ahead of or
behind the reference frequency. The second pair of flip-flops increment
and decrement a counter (54) which in turn controls additional current
sources (78-88) in the charge pump. The additional current sources extend
the linear operating range of the error signal when the phase error
exceeds .+-.2.pi..