微弱周期信号频率检测的一种改进方法  

An improved method of frequency detection of weak periodic signals

作　　者：姜乃卓[1] 陈孝桢[1] 

机构地区：[1]南京大学电子科学与工程系

出　　处：《实验技术与管理》2009年第8期32-35,共4页Experimental Technology and Management

摘　　要：微弱信号的频率检测是微弱信号处理的一个重要内容，也是判定微弱信号幅度和相位的重要前提。文章提出一种方法，将AD采样数据先用结构函数算法粗略判定信号频率，然后进行数字预滤波，最后再次使用结构函数算法准确测定频率。该方法完全数字化，在带AD采样和存储器的微处理器系统上均可实现，编程简单，且不要求实时性，很容易在本科生的微弱信号检测实验中实施。实验证明，该算法对于信噪比为-20dB以上的信号都具有很好的频率检测精度。在实验中提高采样AD的位数、采样频率、采样点数可进一步提高检测精度。The frequency detection of weak periodic signals is an important part of weak signal processing, and also an important precondition of gaining the amplitude and phase information of the original weak signal. A method is put forward, which the frequency of weak periodic signal is probably measured first with structure function algorithm after the signal is sampled by AD, then digital filter is used, and the frequency is measured precisely with structure function algorithm at last. The algorithm, which is fully digitized, can be realized in system which has sampled AD and memory device. Because the programme is easy and realtime is not necessary, the method can be easily achieved in weak signal detection experiment which mainly focuses on undergraduate students. It is proved that the high precision of frequency detection can be acquired when ratio of signal to noise is above 20 decibel in experiment. Detection precision can be enhanced by more bits of sample AD, higher sample frequencies and more sample dots.

关 键 词：微弱信号 信噪比 结构函数 

分 类 号：TP911.23[自动化与计算机技术]