Timing recovery frequency error detector for sampled amplitude magnetic recording

摘要

In a synchronous read channel for magnetic recording, a timing recovery phase-locked loop (PLL) comprises an improved discrete time frequency error detector for locking the PLL to a sinusoidal reference signal. The sinusoidal reference signal is sampled, and a frequency error is computed using three sample values which span more than half a period of the reference signal. Consequently, the frequency error detector is not affected by a DC offset in the reference signal, and it is less susceptible to noise due to an increase in sensitivity.