CAJ | 학술논문

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。
침대 DMR 계통중접수단수요완성대이급중빈신호처리적실제정황，개소료수자하변빈적원리화연건실현적산법류정，제출료소상추취려파기화반파대추취려파기급련적강속추취산법，분석료기우 Cordic 산법 NCO 강저잡산적방법，논술료 ISOP 보상려파기적실현방안，완성료각개자모괴적방진분석。여희이백특정교변환처리중빈신호적방진대비결과현시，수자하변빈산법적성능요교전자요호1 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.