Figure 2.
Block diagram of a first-order infinite impulse response length (IIR) filter with transfer function HS(f ) equivalent to (11) or (12). Elements denote a delay of one trial. At the adder element ⊕, updating of the weighted output γS·cS,k(n − 1) of the last trial n − 1 with the weighted input (1 − γS)·gk(n − 1) of the last trial results in the current output cS,k(n). Note that via γS·cS,k(n − 1), all preceding inputs (and outputs) influence the current output, though for the short-term memory, the influence of trials not in the recent past is negligible.