Repetitive feed-forward algorithm for self-servo-write PLL

A phase error reduction method, comprising:

• generating source timestamps for a plurality of synchronization marks in a source signal using a clock;
• generating a plurality of target timestamps;
• determining phase errors between said source timestamps and said target timestamps;
• minimizing said phase errors;
• and
• removing harmonics of said phase errors using a weighted moving average filter (MAF),
• wherein removing said harmonics further comprises using a repetitive feed forward (RFF) algorithm implemented by:
• scaling said phase errors;
• generating RFF commands to reduce said phase errors;
• filtering said RFF commands with said weighted moving average filter (MAF);
• and
• providing sums of scaled phase errors and filtered RFF commands to a delay buffer.

A phase error reduction system, comprising:

• control means for generating source timestamps for a plurality of synchronization marks in a source signal using a clock and generating a plurality of target timestamps;
• phase-locked loop (PLL) means for determining phase errors between said source timestamps and said target timestamps and for minimizing said phase errors;
• and
• harmonic removal means that communicates with said PLL means for removing harmonics of said phase errors using weighted moving average filter (MAF) means for filtering said harmonics,
• wherein said harmonic removal means further comprises repetitive feed forward (RFF) means for removing said harmonics, and wherein said RFF means includes:
• amplifier means for scaling said phase errors;
• delay buffer means for generating RFF commands to reduce said phase errors;
• said weighted moving average filter (MAF) means for filtering said RFF commands;
• and
• summing means for providing sums of said phase errors scaled by said amplifier means and said RFF commands filtered by said weighted MAF means to said delay buffer means.