Disk drive using preamble and postamble to adjust asynchronous signal samples of payload

A method of operating a disk drive comprising a head actuated over a disk, the method comprising:

• writing data to the disk, the data comprising a first periodic pattern, a payload, and a second periodic pattern;
• first reading the data from the disk to generate a first read signal;
• sampling the first read signal asynchronously to generate first asynchronous signal samples;
• processing the first asynchronous signal samples representing the first periodic pattern to measure a first phase;
• processing the first asynchronous signal samples representing the second periodic pattern to measure a second phase;
• generating a first phase error based on a difference between the first phase and the second phase;
• adjusting the first asynchronous signal samples representing the payload in response to the first phase error to generate first adjusted asynchronous signal samples;
• second reading the data from the disk to generate a second read signal;
• sampling the second read signal asynchronously to generate second asynchronous signal samples;
• processing the second asynchronous signal samples representing the first periodic pattern to measure a third phase;
• processing the second asynchronous signal samples representing the second periodic pattern to measure a fourth phase;
• generating a second phase error based on a difference between the third phase and the fourth phase;
• adjusting the second asynchronous signal samples representing the payload in response to the second phase error to generate second adjusted asynchronous signal samples;
• and
• phase aligning the first adjusted asynchronous signal samples and the second adjusted asynchronous signal samples.

A disk drive comprising:

• a disk;
• a head actuated over the disk;
• and
• control circuitry operable to:
• write data to the disk, the data comprising a first periodic pattern, a payload, and a second periodic pattern;
• first read the data from the disk to generate a first read signal;
• sample the first read signal asynchronously to generate first asynchronous signal samples;
• process the first asynchronous signal samples representing the first periodic pattern to measure a first phase;
• process the first asynchronous signal samples representing the second periodic pattern to measure a second phase;
• generate a first phase error based on a difference between the first phase and the second phase;
• adjust the first asynchronous signal samples representing the payload in response to the first phase error to generate first adjusted asynchronous signal samples;
• upsample the first asynchronous signal samples by at least a factor of ten to generate upsampled signal samples;
• and
• adjust the upsampled signal samples in response to the first phase error.

A method of operating a disk drive comprising a head actuated over a disk, the method comprising:

• writing data to the disk, the data comprising a first periodic pattern, a payload, and a second periodic pattern;
• first reading the data from the disk to generate a first read signal;
• sampling the first read signal asynchronously to generate first asynchronous signal samples;
• processing the first asynchronous signal samples representing the first periodic pattern to measure a first phase;
• processing the first asynchronous signal samples representing the second periodic pattern to measure a second phase;
• generating a first phase error based on a difference between the first phase and the second phase;
• adjusting the first asynchronous signal samples representing the payload in response to the first phase error to generate first adjusted asynchronous signal samples;
• upsampling the first asynchronous signal samples by at least a factor of ten to generate upsampled signal samples;
• and
• adjusting the upsampled signal samples in response to the first phase error.