Design of linear phase paraunitary filter banks with suboptimal coding gain without nonlinear optimization
First, we design a low-pass filter with some regularities and then M/2-1 highpass and bandpass filters are designed such that each filter has minimum compaction gain. The cost function which consists of the frequency constraint, orthogonal condition and the variance of output signal is expressed in quadratic form of the filter coefficients. Consequently, the cost function can be minimized by solving linear equations iteratively without using nonlinear optimization.