频率混叠在时域和频域现象中的研究  

Study on Frequency Aliasing in Time and Frequency Domains

作　　者：应怀樵 沈松 刘进明 

机构地区：[1]东方振动和噪声技术研究所,北京100085

出　　处：《振动．测试与诊断》2006年第1期1-4,共4页Journal of Vibration,Measurement & Diagnosis

基　　金：国家自然科学基金资助项目(编号:10172064;10572101)。

摘　　要：频率混叠(混淆)是数字信号处理中的特有现象,产生频率混叠后,信号处理会得出错误的分析结果。由于从模拟信号测试分析转入数字信号测试分析领域,很容易模糊频率混叠的概念,忽视频率混叠的现象。指出了频率混叠的危害及其在频域与时域中的现象,提出了混叠频率和混叠次数的计算公式,对避免和减少混叠现象的若干方法进行了讨论,并通过对混叠产生机理的研究,得出仅用数字滤波不能替代硬件抗混叠滤波的结论。Frequency aliasing is one of the important concepts in digital signal processing. Frequency aliasing causes incorrect signal-processing outcomes. When turning from the realm of the analogsignal testing and analysis to that of the digital, the frequency aliasing is often confusing and ignored. This paper presents the aliasing harmfulness and its expression in the frequency and time domains, and the formula of aliasing frequency calculation is put forward. Several methods to suppress the aliasing are discussed also. Through researchs on the mechanism of aliasing, a conclusion is given that the only digital filter cannot substitute the anti-alising filter hardware.

关 键 词：采样 频率 混叠 信号处理 

分 类 号：TN991.6[电子电信—信号与信息处理]