Efficient digital filter structures based on allpass filter sections

In this paper, efficient structures of IIR digital filters, variable filters, two-channel and multi-channel banks, Hilbert transformers ad differentiators are presented. All of the filter structures presented in this paper are based on all-pass sections. Structures are based on IIR elliptic minimal Q-factors filters or IIR half-band filters with approximately linear phase. Presented structures have been implemented, verified and optimized regarding sensitivity, number of multipliers or implemented as structures without multipliers. Structures designed with such approach are suitable for implementation with short word length which means that they are suitable in applications where high efficiency is required.