Patent ID: 8284510

Claim:
A method comprising: recording time stamps for a repeating characteristic of a spindle back electromotive force (BEMF) signal; comparing one or more of the recorded time stamps for the repeating characteristic of the spindle BEMF signal with an expected value for the one or more recorded time stamps to detect a timing error associated with writing a servo pattern on a machine readable medium of a self-servo write (SSW) system; and correcting the timing error, wherein the correcting the timing error comprises re-starting a phase locked loop (PLL) that locks a reference clock to the servo pattern on the machine readable medium, and re-aligning the timing for writing the servo pattern by using a sync mark of a servo pattern written on the machine readable medium, wherein the spindle BEMF signal comprises a digital signal, and wherein the repeating characteristic comprises a zero crossing of the spindle BEMF signal.