一种非均匀采样下小信号的检测方法

非均匀采样由于其具有不受采样频率限制、频率分辨率高以及抗混叠等优点,使得其应用十分广泛。但非均匀采样会引起信号的频谱噪声,这样使得非均匀采样下小信号的检测不易实现。本文分析了非均匀采样引起频谱噪声的原因,提出一种基于非均匀采样的小信号检测方法。该方法根据非均匀采样检测得到的大幅度信号,应用陷波器将其消除,降低了由大信号引起的频谱噪声,从而检测出小信号。文中详细说明了陷波方法的原理、陷波器宽度和深度的选择、陷波器中心频率的确定以及陷波器在非均匀采样下的应用,最后给出实验结果。理论和实验表明,基于非均匀采样的陷波方法是一种行之有效的信号频率检测方法,使用该方法处理信号可以得到准确的频率估计效果,检测出信号幅度相差100倍以上的多个信号频率。

A Novel Method for Signal Detection Based on Nonuniform Sampling

The theory of nonuniformly sampling is widely used because of its many advantages, such as avoiding aliasing in signal analysis, processing signals with components whose frequencies exceed the Nyquist limit, and higher frequency resolution than ordinary uniform sampling. The disadvantage of nonuniformly sampling is there exists the noise in spectrum analysis, so it's difficult to detect the low amplitude signals. A novel notch filter method for nonuniform sampling is proposed in this paper. This method is very effective to suppress noise of spectrum by filtering the signal with the maximal amplitude so that it can detect the low amplitude signal. The fundamental of notch filter and threshold filtering are introduced, the characteristics of the notch filter are analyzed, and the processing procedure of notch filter is presented. The results of the experiments show that it is an effective method for signal detection and it can estimate exactly the frequencies of sinusoidal signals when the ratio of amplitude of signal exceeds 100.