Patent ID: 8797670

Claim:
A data storage system, comprising: a tape channel for reading precoded data from a magnetic tape medium to produce a signal; a noise whitening filter positioned subsequent to the tape channel and configured to pass the signal to a soft detector, wherein the noise whitening filter is configured to control variance of noise affecting the signal output from the filter, wherein the noise whitening filter processes the signal according to the following transfer polynomial: W(D)=1−(p 1 D+ . . . +p λ D λ ), where p 1 . . . P λ are the noise whitening coefficients with the noise whitening filter having 2 λ states, and where the tape channel is characterized by a transfer polynomial F(D)=1+f 1 D+ . . . +f L D L where D is delay corresponding to bit duration, with the tape channel having 2 L states, L represents a memory length of the tape channel, and λ represents a memory length of the noise whitening filter; the soft detector configured to calculate first soft information about each bit of the signal and sending the first soft information to a soft decoder; and the soft decoder positioned subsequent to the soft detector, the soft decoder being configured to calculate second soft information about each bit of the signal and sending the second soft information to the soft detector, wherein the precoded data comprises a characteristic of being passed through at least one precoder prior to being written to the magnetic tape medium, and wherein the soft detector provides automatic compensation for the precoded data.