Dependence of signal detection efficiency on control parameters. D = 0.5, A = 0.006, ω = 0.02, . (a) SPD_x plotted against γ with and . SPD for I(t) is drawn for comparisons. There is an optimal , providing the largest SPD_x which is much higher than SPD_I. (b) The same as panel (a) with SPD_x plotted versus E₀ with and . SPD_x increases as E₀ and saturates to a value . (c) The same as panel (a) with SPD_x versus θ for . SPD_x reaches its maximum at . The results of panels (a), (b), and (c) show convincingly that the additional parameters of the filter can dramatically influence the efficiency of signal detection, and enhance the efficiency considerably higher than the input at some optimal parameter sets. Panels (d), (e), and (f) represent ratios corresponding to panels (a), (b), and (c), respectively.