| In order to design 2-D digital systems with variable characteristics, product-separable IIR filters with feedbacks in each dimension are studied. The stability and response of such systems with different situations are analyzed and discussed.; Belonging to one of the methods of generation of VSHP in z-domain, product-separable IIR filters with dimensional feedbacks offer variable characteristics. The variable feedback gain in one-dimension is analyzed with all the other coefficients based on Schussler's Theorem. The stable conditions for the feedback in terms of other coefficients are obtained and hence a stable range of the feedback gain is determined.; Within the stable range of feedback in each dimension, different filters' 2-D frequency responses have been studied and observed with different situations. Significant variable characteristics and different 2-D symmetries are shown with stable responses. Relations between the feedback and response are discussed. Furthermore, to extend this analysis to higher order systems, a computerized analysis method and algorithm is proposed and implemented. This approximation method can work with any order of IIR or FIR filters and has low computation complexity.; More complex systems with variable characteristics can be composed and examples of Image Processing with these filters are simulated as space-domain applications. |
