Disk drive adjusting digital phase locked loop over sector data with frequency induced phase error measured over preamble

A disk drive comprising:

• a disk comprising a sector comprising a periodic pattern and sector data;
• a head actuated over the disk;
• and
• control circuitry comprising a signal sampler, the control circuitry operable to:
• read the sector with the head to generate a read signal;
• sample the read signal at a sampling frequency with the signal sampler to generate signal samples;
• process the signal samples representing the periodic pattern to measure a frequency induced phase error based on kδ, where k represents a signal sample index and δ is a fraction of 2π;
• process the signal samples representing the sector data to generate a data phase error;
• adjust the data phase error in response to the frequency induced phase error to generate an adjusted data phase error;
• and
• control the signal sampler in response to the adjusted data phase error.