Patent ID: 7012937

Claim:
A method of determining a frequency at which a terminal transmits a transmission signal, said terminal comprising a receiver including a delay lock loop circuit, the method comprising: receiving an input signal at said receiver; sampling said signal at a clock rate to generate signal samples; providing said signal samples to said delay lock loop circuit, wherein said delay look loop circuit comprises at least a third order loop and a low order gain loop; controlling said delay lock loop circuit to provide an output representing a phase delay of the received signal, and initially using said low order gain loop and subsequently using said at least third order loop to provide said output; adjusting the clock rate based on said phase delay; determining said frequency at which said terminal transmits said transmission signal based on said phase delay; and determining a difference between said frequency and an expected frequency; and wherein the step of controlling said delay lock loop further comprises using said low order gain loop until said difference is less than a threshold value, and subsequently using said at least third order loop.