Patent ID: 9129647
Filing Date: 2015-09-08
Classification: G11B

Abstract:
1. A servo system comprising: a hardware equalizer circuit operable to filter digital servo data samples according to filter tap coefficients to yield equalized data; a hardware detector circuit operable to apply a data detection algorithm to the equalized data to yield hard decisions; a convolution circuit operable to convolve the hard decisions with a target response to yield ideal digital data; a subtraction circuit operable to subtract the ideal digital data from the equalized data to yield an adaptation error signal; an error gradient calculator operable calculate an error gradient signal based at least in part on the adaptation error signal, wherein the error gradient calculator is operable to calculate the error gradient signal by multiplying the digital servo data samples with the adaptation error signal; a tap adaptation circuit operable to calculate values of the filter tap coefficients based on the error gradient signal; and a second error gradient calculator operable to calculate a second error gradient signal based on the hard decisions and on the adaptation error signal, wherein the convolution circuit is further operable to adapt the target response based on the second error gradient signal.