IIR Cascaded-Resonator-Based Filter Design for Recursive Frequency Analysis

The cascaded-resonator (CR)-based filter structure has been proposed in previous works as a convenient approach to the dynamic harmonic analysis. This CR filter can be with multiple resonator (MR) poles or ones dispersed properly. In all previous papers the resulting filters of the CR structure are finite-impulse-response (FIR)-type. In this letter, the aim is to use the infinite-impulse-response (IIR) CR-based filters for a full spectrum estimation. Thanks to the linearized model, including stability conditions, filter coefficients of the IIR filter transfer function are derived through the minimax optimization using a linear programming. This way, the frequency responses of the harmonic analyzer can be improved in accordance with actual requirements, sometimes even without any increase of computational burden.