任意采样率变换数字重构滤波器设计

针对理想重构函数在数字信号域不可实现而直接截取性能较差的情况,根据信号重构理论和FIR（Finite Impulse Response,有限脉冲响应）滤波器窗函数设计法,分析不同窗函数、不同截取长度对重构滤波器的影响,提出一种凯塞窗任意采样率变换数字重构滤波器设计方法.该方法通过选择合适的窗参数、截取长度、重构滤波器时域精度和量化位数,有效控制阻带最小衰减抑制数字重构镜像.设计的数字重构滤波器已成功应用于某卫星基带调制解调器,符合镜像抑制大于65 dB的性能要求.

Design of Digital Reconstruction Filters with Variable Sample Rate

Following analysis of the influence of different window functions and different truncation length on recon- struction filters in accordance with signal reconstruction theorem and window function design method of FIR （Finite Impulse Response） filter, a design method of digital reconstruction filters with variable arbitrary sample rate is pro- posed using Kaiser window as ideal reconstruction is impossible in digital signal processing while its direct truncation doesn＇t perform well. Through selection of appropriate window parameters, truncation length, time accuracy of re- construction filter and quantization bits, the method effectively controls the minimum stopband attention to suppress the reconstruction image. The designed reconstruction filter is successfully used in a satellite baseband modem and its image suppression is greater than 65 dB, meeting desired performance requirements.