System for estimating carrier frequencies of quadrature amplitude modulated signals having high symbol rates

A system for estimating carrier frequency of an applied QAM signal relative to a target carrier frequency, comprising:

• a converter, converting the applied QAM signal to a complex IF signal and digitizing the complex IF signal at a predesignated sample rate;
• an exponentiator, raising the complex IF signal to a predesignated power;
• a FFT module, performing a FFT, having a predetermined number of samples, on the complex IF signal as raised to the predesignated power;
• and
• a processor, taking the magnitude of the resulting FFT, extracting the index of a sample within the resulting FFT having the greatest magnitude and estimating the carrier frequency of the applied QAM signal relative to a target carrier frequency based on the predesignated power, the extracted index, the predetermined number of samples and the predesignated sample rate.

A system for estimating carrier frequency of an applied QAM signal relative to a target carrier frequency, comprising:

• a converter, converting the applied QAM signal to an IF signal and digitizing the IF signal;
• a quadrature downconverter, receiving the digitized IF signal, extracting a baseband in-phase component of the digitized IF signal, extracting a baseband quadrature component of the digitized IF signal and generating a complex signal from the baseband in-phase component and the baseband quadrature component;
• an exponentiator, raising the complex signal to a predesignated power;
• an FFT module, performing a FFT, having a predetermined number of samples, on the complex signal as raised to the predesignated power;
• and
• a processor, taking the magnitude of the resulting FFT, extracting the index of a sample within the resulting FFT having the greatest magnitude and estimating the carrier frequency of the applied QAM signal relative to a target carrier frequency based on the predesignated power, the extracted index, the predetermined number of samples and the predesignated sample rate.