Patent ID: 8331208

Claim:
An information readout device comprising: an equalizer configured to include a second-order Volterra filter, and equalize a readout signal read out from an information recording medium to a predetermined characteristic to output said equalization signal; and a maximum likelihood detector configured to output a binary signal through maximum likelihood detection based on said equalization signal, wherein calculation is performed while the number of second-order terms included in calculation processing by said second-order Volterra filter is limited to three or four, and wherein said second-order terms included in said calculation processing by said second-order Volterra filter is expressed by four terms: x(k+1−M)·x(k−M), x(k+1−M)·x(k−1−M), x(k−M)·x(k−M), and x(k−M)·x(k−1−M), where x(k) is a signal group in which said readout signal is discretized by time and M is a predetermined fixed number.