Aiming at the problem of small stopband attenuation of discrete Fourier transform modulated filter bank(DFTMFB)

a method that is used to design novel interleaved discrete Fourier transform modulated filter banks(IDFTMFB)is presented. The analysis filter bank of IDFTMFB is generated by alternately modulating two analysis prototype filters with complex exponential function

and the synthesis filter bank of IDFTMFB is generated from two synthesis prototype filters via the same modulating manner. The interleaved modulation method used by IDFTMFB provides more flexibility in its structure design. Based on the requirements on the passband

stopband

and system distortion of the filter bank

the design of the IDFTMFB prototype filters is converted into a non-linear optimization problem. Since the discretization operation of continuous parameter in the design of conventional DFTMFB is avoided

the proposed algorithm is simple. Simulation results show that the improvement on the stopband attenuation of the complex modulated filter bank obtained by the proposed method is approximately 3 dB higher than the traditional DFTMFB method

the improvement on the output distortion is up to approximately 12 dB

while the output aliasing is reduced approximately 1 dB.