Patent ID: 8508879

Claim:
An apparatus comprising: clock circuitry configured to produce a write clock signal and a servo clock signal; circuitry configured to process a waveform produced by a read head operated with respect to a recording medium, the medium comprising magnetic bit cells arranged on tracks; circuitry configured to produce, based on the waveform, a servo detect pulse that indicates a detection of servo data; circuitry configured to measure a timing difference that is based on the servo detect pulse and a write pulse of the write clock signal; circuitry configured to control an adjustment of a phase of the write clock signal based on the timing difference to align the write clock signal with at least a portion of the bit cells; circuitry configured to operate a counter to count clock pulses of the write clock signal; and circuitry configured to produce a write clock sync pulse based on N increments of the counter, wherein N represents a number of bit cells in an area defined by a distance, on a track of the medium, from a first servo sync mark to a second servo sync mark, wherein the circuitry configured to measure the timing difference is responsive to the write clock sync pulse.