Abstract

A new approach to generate 2-D filters having variable magnitude characteristics from an active analog doubly terminated network has been proposed. An active analog circuit with reactance elements in T section in the feedback has been considered. Its stability has been ensured and a 2-D analog lowpass filter has been generated. The impedance values for the filter is obtained in comparison with type I Chebyshev filter with 1 db ripple in the pass band. The 2-D analog lowpass filter has been transformed to digital domain by applying the generalized bilinear transformation. Similarly 2-D digital high pass filter has been obtained. The 2-D digital bandpass filter has been obtained by cascading the lowpass and highpass filters. The 2-D digital filters are studied under five different cases. These five different cases are based on the coefficients of generalized bilinear transformation and the op-amp gain parameter. The effect of each generalized bilinear transformation coefficient and the op-amp gain on the filter output is studied by individually varying them. Finally, performance comparison between the infinite gain and finite gain configuration has been done for the lowpass filter with a basic image processing application. A basic application for 2-D digital highpass filter with finite gain has been illustrated in image processing.