A design of two-dimensional (2D) digital filter with monotonic amplitude-frequency responses using Darlington-type gyrator networks by the application of Generalized Bilinear Transformation (GBT). The advantage of the proposed method is that the resulting 2D digital filters provide stable monotonic amplitude-frequency responses, desired cutoff frequencies and bandwidths. A digital filter transformation method is also proposed in this paper and the concept of the method is that the coe±cients of a digital transfer function which is transformed from a stable 2D analog Darlington-type gyrator...