摘要
由于非均匀采样具有不受采样频率限制、频率分辨率高及抗混叠能力强等优点,使得其应用十分广泛。但非均匀采样会产生频谱噪声,这使得小信号的检测变得困难。为此,本文在分析非均匀采样产生频谱噪声原因的基础上,提出了2种检测小信号的新方法——逐层滤波法和增强频谱幅度法。前者通过一个可随时改变中心频率的滤波器来实现;而后者通过非均匀周期采样和真实信号频谱幅度累加来实现。文中分别给出仿真结果,并且通过理论和仿真结果验证了所提方法的有效性。
Non-uniform sampling is widely used because of its merits, such as freeing from restriction of sampling frequency, high frequency resolution and anti-aliasing. But it is difficult to detect the low amplitude signals, owing to interference of spectrum noise from non-uniform sampling. Therefore, the reasons why non-uniform sampling causes spectrum noise were given. And filtering in one by one and augmenting amplitude of frequency from real signals to detect low amplitude signals were put forward. The former was realized by the filter, the center frequency of which may randomly change; the latter was done by non-uniform periodical sampling and augmenting amplitude of frequency. The results of emulation were given in this paper. The validities are proved by theory and results of simulation.
出处
《国外电子测量技术》
2007年第2期38-41,共4页
Foreign Electronic Measurement Technology
关键词
非均匀采样
检测
小信号
频谱噪声
non-uniform sampling
detecting
low amplitude signals
noise of spectrum
