Perceptual Echo Control and Delay Estimation 111 Fig 13 Sparseness measure and its impaction on length of adaptive filter The quantity in Eq (56) represents an energy measure in [dBm] within an estimated impulse response Fig 14 demonstrates the curve for this parameter for two frequency domain algorithms It can be observed that after 0.5 seconds estimation of IR energy measure for IPMDF stops fluctuating Consequently, this fact can be used for switching between different adaptation schemes Fig 14 Estimated misalignment and energy measure for MDF and IPMDF algorithms 112 Adaptive Filtering Applications Before representing the proposed MDF scheme, declare the following statements: I Utilization of sparseness measure, 0