Patent ID: 6233292
Filing Date: 2001-05-15
Classification: H03J

Abstract:
A digital communication device comprising a receiver having a mixer which is coupled to a local frequency generating arrangement, a demodulator which is coupled to the receiver, a microcontroller which is coupled to the demodulator being arranged for providing a frequency offset value being a difference between a frequency value representative of an output of the local frequency generating arrangement and a frequency value representative of a desired tuning frequency, and frequency adjustment means for adjusting the frequency of the local frequency generating arrangement in dependence of the frequency offset value, the microcontroller being arranged for processing the frequency offset value such that long term frequency drift is separated from short term frequency drift, the frequency adjustment means comprising a frequency adjustment reference value which is updated in accordance with the separated long term frequency drift, the microprocessor being arranged to perform separated short term drift compensation and long term drift compensation, the short term drift compensation being performed on the basis of the separated short term frequency drift and the long term drift compensation being performed on the basis of the frequency adjustment reference value, and the short term drift compensation being performed at first time intervals that are substantially shorter than second time intervals of performing the long term drift compensation.