Patent ID: 8743498

Claim:
A data storage system, comprising: a tape channel for reading data from a magnetic tape medium to produce a signal; a noise whitening filter positioned subsequent to the tape channel configured to receive the signal, wherein the noise whitening filter is configured to minimize variance of its output signal; a soft detector configured to receive output from the noise whitening filter, the soft detector configured to calculate first soft information about each bit of the signal and send 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 send the second soft information to the soft detector, wherein the soft detector applies a Dual-MAX (DMAX) algorithm, and wherein the noise whitening filter is configured to process the signal according to the following transfer polynomial: W(D)=1−(p 1 D+ . . . +p λ′ D λ ), where p 1 . . . p λ′ are noise whitening coefficients, where D is delay corresponding to bit duration and where the tape channel transfer polynomial is characterized F(D)=1+f 1 D+ . . . +f L D L , with 2 L being a number of states of the tape channel, wherein the soft detector has a total of 2 L+λ states, the noise whitening filter comprises 2 λ′ states, and λ′ is greater than λ, wherein L represents a memory length of the tape channel, and wherein λ represents a memory length of the noise whitening filter.