METHOD AND APPARATUS PROVIDING AN AMPLITUDE INDEPENDENT AUTOMATIC FREQUENCY CONTROL CIRCUIT

摘要

An automatic frequency control (AFC) loop circuit includes a mixer for mixing a local oscillator signal with a received signal to generate a result signal; a frequency detector coupled to the result signal and outputting a loop error signal; a combiner circuit for combining error signals output from a plurality of fingers of a rake receiver with the loop error signal output fom the frequency detector to generate a combined loop error signal; a sign detector having an input coupled to an output of said combiner circuit for outputting a sign detector ouput signal for indicating a sign of the combined loop error signal; control circuitry for controlling a frequency of the local oscillator signal in accordance with the sign detector ouput signal and a loop filter partitioned into a first loop filter coupled between the output of the frequency detector and an input to the sign detector.