关键词: 频率响应遮蔽, 改进型离散傅里叶变换, 重构误差, 滤波器组, 信道化器

Abstract: This paper proposes a nearly perfect reconstruction onboard channelizer of low complexity combining frequency response masking (FRM) with modified discrete fourier transform (MDFT). Of the two techniques,the FRM structure can design a lowpass finite impulse response (FIR) prototype filter with a steep transition band with low complexity, while the MDFT filter bank structure can mostly eliminate the adjacent band aliasing. Replacing the structure of the FRM that is not suitable for the adjacent band splicing by a highpass and lowpass filter complementary structure,the splice jitter can be reduced. The upsampling rate in the MDFT structure is adjusted to make it suitable for the oddeven split channelizers. Then a new structure is put forward, which is more suitable for nonuniform bandwidth applications. Simulations show that this method has a lower computational complexity, a steeper transition band and narrower guard interval, and a smaller reconstruction error.

Key words: frequency response masking (FRM), modified discrete Fourier transform (MDFT), reconstruction error, filter bank, channelizer