Feed-forward timing recovery for digital magnetic recording

Square-law and fourth-power timing recovery for magnetic recording channels modeled by a Lorentzian transition response are investigated. It is shown that these timing recovery techniques perform extremely well at practical linear densities. It is also shown that the feed-forward timing recovery overcomes a lot of problems associated with decision-directed timing recovery at low input signal-to-noise ratios. Bit-by-bit simulations show that the square-law timing recovery performs better than the fourth-power timing recovery