摘要
介绍了软件无线电短波接收机中数字下变频(digital down conversion,DDC)的基本原理和应用,以及数字下变频的一般结构。DDC主要是将中频信号和NCO产生的载波信号进行混频,再经过LPF虑除高频分量得到基带信号,从而实现下变频的功能。分别介绍了查表法和应用CORD IC算法实现DDC的过程。
This paper introduces the basic principle and the application of digital down conversion （ DDC ） based on software radio and the general structure of DDC. The signal of intermediate frequency and the signal of carrier wave were mixed up in the DDC, the mixed signal passed through lowpass filter, and thus the function of down conversion was implemented. The paper presents the lookup table and the process of using CORD IC to realize DDC.
出处
《数字通信》
2010年第1期74-76,共3页
Digital Communications and Networks
关键词
软件无线电
数字下变频
数字控制振荡器
查表法
CORD
IC
software radio
digital down conversion （DDC）
numerical controlled oscillator （NCO）
lookup table
CORD IC
