| 摘要 |
The present invention provides a frequency tracking and compensation system and methods for minimizing the frequency offset between remote and local units of a communications system. The system of the present invention resides in the local unit and comprises a downconverter, a digital transceiver, a processor, a reference oscillator and a frequency synthesizer. The downconverter mixes a signal received from the remote unit with a local oscillator (LO) signal generated by the frequency synthesizer. The frequency of the LO signal is based on the frequency of a reference signal generated by the reference oscillator. The system of the present invention utilizes the digital transceiver to determine a frequency offset of the received signal without comparing the received signal to the reference signal. The processor then utilizes the frequency offset to adjust the frequency of the reference signal. The method of the present invention accumulates the frequency offsets and compares the accumulated offset to a predetermined threshold. The reference frequency is adjusted if the accumulated offset exceeds the threshold. In one embodiment, the reference frequency is adjusted after complete reception of each call.
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