“…The L 1 , L 2 (or least-squares), and L∞ (or Chebyshev, Minimax) approximation criteria are commonly used. Minimax design [5,6] was used, where the peak errors were more important than the total squared errors, and least-squares design [7,8] was used, where the total squared errors were more important. When single norm approximation criterion is not appropriate in many applications, the mix-norm criterion is used, in which some constraints are imposed on the passbands or/and stopbands, e.g., the peak constrained weighted least square error (PCWLSE) FIR filters design [9,10] , equiripple passbands and peak-constrained least-squares stopbands design [11] , the mean-square stopbands (passbands) constrained least square passbands (stopbands) design [12] , and so on.…”