Linear-phase paraunitary filter banks with complex-valued frequency responses
In this paper, a new design algorithm for complex-valued paraunitary filter banks with conjugate symmetry is proposed which leads the analysis and synthesis filters to have linear-phase frequency responses. The lattice structures proposed in this paper can be treated as a generalization of the factorization of real-valued linear-phase filter banks. Pure-imaginary filter banks can be designed as a special case in the new algorithm. Implementation algorithms and design results of complex-valued filter banks with 8 and 16 channels are included to verify the lattice structures in the design. The filter banks demonstrate linear-phase characteristics in both the time and frequency domain.