Method and apparatus for estimating sampling frequency offset, and sampling timing recovery loop including the apparatus

A sampling timing recovery loop comprising:

• an interpolator which interpolates a discrete data signal and outputs a sample data signal;
• a waveform characteristic extraction unit which outputs a waveform characteristic value corresponding to a waveform characteristic of a training sequence period in one frame period of the sample data signal;
• a variation quantity calculation unit which calculates a waveform characteristic variation quantity based on a waveform characteristic value in an m-th frame and a waveform characteristic value in an (m−k)-th frame, where m and k are independently integers of 1 or more;
• an SFO (sampling frequency offset) estimator which estimates an SFO of the sample data signal based on the waveform characteristic variation quantity;
• a loop filter which filters the sampling frequency offset output from the SFO estimator and outputs an offset information signal;
• and
• a controller which outputs an offset control signal corresponding to the offset information signal to the interpolator so as to correct a sampling timing error of the sample data signal.