Patent ID: 6697609
Filing Date: 2004-02-24
Classification: H04L

Abstract:
A carrier reproducing apparatus for reproducing the carrier of a received signal, comprising:a first multiplying circuit for multiplying the received signal with a first feedback signal; a filter circuit for filtering the first multiplying circuit to remove a signal component having a frequency adjacent to carrier frequency; a second multiplying circuit for multiplying the filtered signal with a second feedback signal; a phase detection circuit for detecting a phase of a signal output from said second multiplying circuit and generating a phase signal; a first numerical control circuit for generating said second feedback signal having an oscillation frequency in accordance with said phase signal; a lock detection circuit for detecting a locked state of a phase of the signal output from said second multiplying circuit based on said phase signal; a second numerical control oscillation circuit for generating said first feedback signal having an oscillation frequency in accordance with a third signal; and a tracking circuit for controlling said third signal so that said phase signal does not exceed a predetermined value when a phase of the signal output from said second multiplying circuit is locked and the phase signal exceeds said predetermined value.