Patent ID: 7430247

Claim:
A method of detecting a carrier frequency for an N-ary phase modulated signal comprising the steps of: digitizing the N-ary phase modulated signal at a sampling frequency; raising the N-ary phase modulated signal to the N th power to produce a raised power signal; transforming the raised power signal into frequency domain data; evaluating a crest frequency from the frequency domain data, wherein evaluating comprises iteratively fine shifting the center frequency of the N-ary phase modulated signal to a plurality of frequencies around a peak value in the frequency domain data; for each iteration repeating the raising and transforming steps to obtain a plurality of peak values; for each iteration calculating a ratio of peak value to average power for the frequency domain data; finding a maximum ratio from all the iterations; and evaluating a frequency corresponding to the maximum ratio as the crest frequency; and calculating the carrier frequency from the crest frequency.