An apparatus, method, and system for writing data to a hard disk drive
synchronous with an apparent disk speed. The apparatus, method, and
system has a phase-locked loop (PLL) to generate am output clock signal,
wherein a clock interpolator responsive to phase rotation control is in
the PLL feedback loop. The phase rotation control is proportional to the
apparent disk speed, and the PLL output clock signal is also proportional
to the apparent disk speed. A second clock interpolator further modifies
the PLL output clock signal to provide pre-compensation control.