Simple iterative design technique for tree structured non-uniform filter bank

A simple efficient iterative technique for the design of non-uniform filter banks (NUFB) proposed by Soni et al is examined and improved by designing the prototype filters using constrained equiripple finite impulse response (FIR) technique. In this method, instead of optimizing the cut-off frequency, the passband edge frequency (ω_P) is varied iteratively in order to adjust the filter coefficients so that the reconstruction error is optimized to zero. The modified algorithm is simple, and has high design efficiency. The performance of this algorithm is evaluated in terms of computational time (CPU time), reconstruction error (RE) and number of iterations (NOI). Several design examples are included to illustrate the modified algorithm and its improved performances over other exiting methods. Finally, it is exploited for sub-band coding of electrocardiogram (ECG) and speech signal.