DMR系统中数字下变频技术分析  

Technical Analysis of Digital Down- conversion in DMR System

作　　者：陶杰 李骏 张水兴 赵义 

机构地区：[1]无锡市轨道交通发展有限公司,江苏无锡214043 [2]江西赣西供电公司信息通信分公司,江西新余338000 [3]河北远东通信系统工程有限公司,河北石家庄050081

出　　处：《无线电工程》2014年第8期34-37,共4页Radio Engineering

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.

关 键 词：DMR 下变频 NCO 积分梳状抽取滤波器 补偿滤波器 

分 类 号：TP302.1[自动化与计算机技术—计算机系统结构]