APPARATUS AND METHOD FOR RAPIDLY TRACKING FREQUENCY OFFSET

摘要

The present invention discloses an apparatus and a method for rapidly tracking frequency offset, and relates to the field of communication technology. The method includes that: a frequency discriminator determines a first frequency offset between a received system signal and a received local oscillator signal; an automatic frequency control (AFC) loop filter performs smooth filtering on the first frequency offset; a module for locking and rapidly tracking frequency offset determines whether or not step-type frequency offset occurs according to the first frequency offset, resets the AFC loop filter when the step-type frequency offset occurs, and determines an initial frequency offset value of the AFC loop filter according to the first frequency offset and last final frequency offset of the AFC loop filter; when the AFC loop filter works normally, the module for locking and rapidly tracking frequency offset determines the final frequency offset of the AFC loop filter using the initial frequency offset value and the frequency offset output from the AFC loop filter; a voltage controlled oscillator regulates the local oscillator signal according to the final frequency offset and transmits the regulated local oscillator signal to the frequency discriminator. The present invention mainly applies to a communication system in which frequency offset changes rapidly, and can improve reception performance of the system.