Design of near perfect reconstruction prototype filter with FFT interpolation

For higher-order and high complexity in designing perfect reconstruction prototype filter, a novel approach base on interpolation in FFT domain is proposed to design the near perfect reconstruction prototype filter. In our proposed scheme, we employ unconstrained iterative algorithm to obtain low-order model filter with high stopband attenuation, then exploits the FFT transform of model filter to get the discrete spectrum, and interpolates zeros at high-frequency position. Finally, the IFFT transform is performed to get the prototype filter which is suitable for near perfect reconstruction. Moreover, the afore mentioned approach use interpolation of FFT domain in combination with iterative optimizing, which avoids a large number of parameters to be optimized when the prototype filter is designed with a high stopband attenuation. Besides, the image spectrum is saved, which avoids the filter design of image suppressor, and results in the order reduction of the prototype filter and relieves the complexity of design. Simulation results reveal that our proposed method embraces favorable performance improvements compared with the conventional methods.