Patent ID: 7050485

Claim:
A communication system comprising: a receiver that is configured to receive a received signal corresponding to a transmitter of the received signal, an acquisition subsystem, operably coupled to the receiver, that is configured to acquire an acquisition frequency and an acquisition phase of the received signal, and a communication subsystem that is configured to effect communication with the transmitter, based on the acquisition frequency and acquisition phase, wherein the acquisition subsystem includes: a code generator that is configured to generate a code at a controlled phase; a correlator, operably coupled to the receiver and the code generator, that is configured to determine a measure of coherency of the received signal to the code, in at least one of two modes: a fine mode that provides the measure of coherency based on a plurality of measurements of correlation between the received signal and the code at the controlled phase, a quick mode that provides the measure of coherency based on fewer measurements of correlation than the plurality of measurements in the fine mode; and, a controller, operably coupled to the correlator, that is configured to control the correlator so as to: obtain a first plurality of coherency measures corresponding to a first plurality of controlled phases, while the correlator is in the quick mode, determine a coarse phase based on the first plurality of coherency measures, obtain a second plurality of coherency measures correspond to a second plurality of controlled phases, while the correlator is in the fine mode, and determine the acquisition phase based on the second plurality of coherency measures.