Patent ID: 7957088

Claim:
A system comprising: a plurality of synchronous servo channels, each synchronous servo channel receiving a signal from a servo reader of a magnetic head; logic for estimating a tape velocity ({circumflex over (v)}); logic for determining a first time instant ({circumflex over (τ)} 1 ) and second time instant ({circumflex over (τ)} 2 ), each time instant representing a time at which a flag is generated by a related servo channel selected from the plurality of synchronous servo channels; logic for determining a first correction term Δ 1 and a second correction term Δ 2 , each correction term representing a time difference between a time at which a peak of a correlation signal and a time at which the flag occur on the related servo channel; logic for calculating a skew error estimate (Θ err ) based on a reference shift value (Θ ref ) associated with a servo band pair being spanned by a head module included in the magnetic head, where Θ err ={circumflex over (v)}({circumflex over (τ)} 2 −{circumflex over (τ)} 1 +Δ 1 −Δ 2 )−Θ ref ; and logic for applying a first control signal to the skew-following loop, wherein the first control signal includes a skew correction that corresponds to the calculated skew error estimate.