Patent ID: 6639957
Filing Date: 2003-10-28
Classification: H04J,H04L

Abstract:
A method of compensating for reference frequency drift in a communications device, the communications device having a microprocessor arrangement and a local oscillator circuit adapted to generate a reference frequency signal and operate synchronously with a clock circuit of the microprocessor arrangement, the method comprising:a) generating a clock circuit time reference for the clock circuit by dividing the reference frequency signal by a divisor; b) obtaining a synchronization time stamp from a networked reference clock arrangement operably connected to the microprocessor arrangement and synchronizing the clock circuit to the synchronization time stamp; c) obtaining a calibration time stamp from the networked reference clock arrangement after a predetermined time duration has transpired from synchronization of the clock circuit and comparing the calibration time stamp to a current time of the clock circuit; and d) synchronizing the current time of the clock circuit with the calibration time stamp and adjusting the local oscillator circuit as a function of a time variation between the calibration time stamp and the current time of the clock circuit.