Patent ID: 8873614

Claim:
A system comprising: a storage medium; a demodulator configured to (i) receive an input signal from the storage medium, and (ii) demodulate the input signal; and a channel decoder configured to estimate data stored in the storage medium by decoding the demodulated input signal to provide an output signal, wherein the channel decoder comprises a first filter configured to generate a first equalized signal based on the output signal provided by the channel decoder, a first processor configured to, based on the first equalized signal and a first Viterbi algorithm, generate (i) a first estimate of the data, and (ii) an estimate of noise, and a second processor configured to generate a second estimate of the data based on (i) the first estimate of the data, (ii) the estimate of the noise, and (iii) a second Viterbi algorithm, and wherein the output signal comprises the second estimate of the data.