Fig. 2.

Performances of both estimators for model M1 (nonstationary situation, time-varying α[t] for N₀ =768. a) Time course of parameter α[t] (dashed line) and target relationship curve (solid line) averaged over frequency axis. Standard boxplots obtained by Monte-Carlo simulation for different estimators: b) |ρ̂[t, f]|², c) R̂²[t, f] with τ_M = −τ_m = 5, d) R̂²[t, f] with τ_m = τ_M = 0.