DESIGN OF 2-D IIR DIGITAL FILTERS WITH APPROXIMATIVELY FLAT GROUP DELAY CHARACTERISTIC
Saga V. Niltolid, Vidosav Stojanović · 2001
The procedure to the design of two-dimensional recursive digital filters with controllable amplitude characteristic and flat group delay characteristic has been presented. In order to design these filters it is neces- sary to make first maximally flat group delay one-dimensional IIR filter with proposed am- plitude characteristic. Stable two-dimensional IIR transfer function has been obtained us- ing a digital spectral transformation. Tha way for obtaining parameters of digital spec- tral transformation has been also given. This method does not need nonlinear optimization techniques. Obtained two-dimensional filter is guaranteed to be stable, the error between the specified passband contour is very small and amplitude and group delay characteristic of one-dimensional prototype are wll preserved by the two-dimensional filter.