Patent ID: 7480350

Claim:
A carrier recovery apparatus comprising: a first low pass filter for receiving an I baseband signal from a complex multiplier and extracting a pilot component of the I baseband signal by eliminating data components in the I baseband signal, wherein the complex multiplier converts a digital I passband signal and a digital Q passband signal to generate the I baseband signal and a Q baseband signal; a second low pass filter for eliminating data components from the Q baseband signal; a delay for converting the pilot component of the I baseband signal from the first low pass filter to a DC component; a sign extractor for selecting a sign determination level comprising at least one difference value and determining a sign of the I baseband signal output from the delay according to the selected sign determination level; an accumulator for accumulating output signals of the sign extractor and outputting a sign determination level control signal to the sign extractor, wherein the sign determination level is determined according to an average value of the output signals compared to a threshold value; and a multiplier for generating a phase error by multiplying the sign of the I baseband signal and the eliminated data components from the Q baseband signal.