US Patent 7864466 Signal processing apparatus and a signal storage system

In general, circuit scale in a DAE is large. The proposed DAE includes First multipliers, Unit processing circuits and Combined circuits. First multipliers use temporary estimated values to respectively compute signals. Unit processing circuits use the signals, which are multiplication results of the first multipliers, to respectively compute signals. Combined circuits use the signals, outputted from the unit processing circuits, to compute respective logarithm likelihood ratios λ4 and λ5. Here, in the unit processing circuits, by sharing part of circuits related to computing continuous λs, the circuit scale of the DAE is reduced. For example, with regard to computation of λ4 and λ5, part of four unit processing circuits is shared.