On selectivity properties of discrete-time linear networks
S. Signell · IEEE Transactions on Circuits and Systems · 1984
A definition of the quality factorQand the resonant angle\theta_{0}for discrete-time networks is presented. The definitions are based on the bilinear transform. Using this transform, the selectivity properties for discrete-time networks, such as switched capacitor (SC) and digital filters, are consistent with analog networks. Expressions forQand\theta_{0}in terms of polar coordinate parametersrand\theta_{p}for a complex-conjugate pole pair andx_{1}andx_{2}for real-axis poles are given as well as the inverse relations. Canonic expressions for generic forms of a biquadratic function are also given. Finally, an accurate method for measurement of the parameters in second-order SC-filters and digital filters implemented in software is described.