关键词: 数据采集系统, 奈奎斯特采样定理, 抗混叠, 滤波器

Abstract: In a high speed data acquisition system, the signal sampling must satisfy Nyquist’s sampling theorem, otherwise frequency aliasing will occur, and it will lead to the original signal cannot be restored from the sampled signal. In order to eliminate the influence of aliasing on the data acquisition system, a 5-order Butterworth type passive differential anti-aliasingfilter is designed. LTspice simulation software is used to simulate the filter, and the simulated results show that the attenuation characteristics of the designed filter are verified to be relatively flat in the passband. The measured results show that the spurious free dynamic range (SFDR) of the system is 84.32 dB.The designed anti-aliasing filter can effectively eliminate the signal aliasing phenomenon and maintain a good system dynamic performance.

Key words: data acquisition system, Nyquist sampling theory, anti-aliasing, filter