Patent ID: 8023382
Filing Date: 2011-09-20
Classification: G11B

Abstract:
1. An information reproduction apparatus comprising: a branch metric calculation part configured to receive an equalization signal being obtained by applying a waveform equalization to a sampled reproduction signal sequence, and to calculate a plurality of branch metrics based on a sample value of the equalization signal at a time t and a plurality of expectation values; a path metric update circuit configured to calculate a third path metric from a first branch metric included in the plurality of branch metrics and a first path metric being correlated to a first state at a time t−1 based on the plurality of branch metrics, the first path metric and a second path metric being correlated to a second state at the time t−1, and to calculate a fourth path metric from a second branch metric included in the plurality of branch metrics and the second path metric; a path memory configured to hold first path information indicating a first path being correlated to the first state at the time t−1 represented by a channel bit sequence, and second path information indicating a second path being correlated to the second state at the time t−1 represented by a channel bit sequence; a bias output circuit configured to output a first offset value based on the first path information and the second path information which are received from the path memory; and a path metric selection circuit configured to perform a selection among either of the third path metric or the fourth path metric, and to hold a result of the selection with correlating to a third state at the time t.