摘要
针对DMR系统中接收端需要完成对二级中频信号处理的实际情况,介绍了数字下变频的原理和软件实现的算法流程,提出了梳状抽取滤波器和半波带抽取滤波器级联的降速抽取算法,分析了基于Cordic算法NCO降低杂散的方法,论述了ISOP补偿滤波器的实现方案,完成了各个子模块的仿真分析。与希尔伯特正交变换处理中频信号的仿真对比结果显示,数字下变频算法的性能要较前者要好1 dB。
As the receiver need to process the IF signal in DMR system,the principle and software algorithm process of Digital Down-conversion is introduced. CIC decimation filter and Half-Band decimation filter cascade decimation algorithm is proposed. The method to reduce stray of the NCO based on the Cordic algorithm is analyzed.The implementation ISOP compensation filter is expoun-ded.Finally,the simulation analysis of each module is completed.Simulation results show that the performance of DDC algorithm is better than that of Hilbert algorithm with 1 dB.
出处
《无线电工程》
2014年第8期34-37,共4页
Radio Engineering
