基于高调制频率的快速数字锁相算法  

High Speed Digital Lock-in Algorithm Based on High-modulate Frequency

作　　者：蒋国亮[1] 杨晖[1] 李然[1] 

机构地区：[1]上海理工大学光学与电子信息工程学院,上海200093

出　　处：《仪表技术与传感器》2015年第12期126-128,共3页Instrument Technique and Sensor

基　　金：国家自然科学基金(61007002);上海市教育委员会科研创新项目(15ZZ072)

摘　　要：为了提高数字锁相的检测速度以及其最高调制频率,改善数字锁相放大的实时检测性能,文中提出了一种新型快速数字锁相算法。文中根据方波参考信号傅里叶展开存在奇次谐波,使得调制频率等于参考信号频率的2m-1倍。同时,通过将采样频率设为调制频率的4的整数倍,保证两路参考信号的正交性。在相敏检波算法实现中,仅仅存在加减法运算,消除了乘法运算,提高了数字锁相算法的运算速度。而且,基于普通微处理器的数字锁相放大能达到的最高调制频率也得到了有效的提升,改善了锁相放大的实时性能。实验表明,该算法既具备较高的速度,又能提高锁相放大的实时性,使得数字锁相对微弱信号的实时检测在普通微处理器上的实现成为可能。In order to improve the speed and the maximum modulation frequency of the digital lock-in,a high speed digital phase-locked algorithm was presented in this paper. In this paper,a new algorithm that make the modulate frequency equal to 2m-1 of square reference frequency was proposed to implement a lock-in,which was based on odd harmonic components in the square wave reference. The sampling frequency was four times as large as the modulate frequency to insure the reference sequences orthogonal. In the implementation of phase sensitive detection,only additions and subtractions were used,which speed up the computation in lock-in. Furthermore,the maximum modulate frequency of a lock-in was enhanced considerably with a general microprocessor.The results of the experiments show that the new algorithm not only has high speed,but also improves the performance of real-time detection,which makes it possible for a general microprocessor to implement weak signal detection by the new algorithm in real time.

关 键 词：数字锁相算法 调制频率 微弱信号 相关运算 奇次谐波 方波参考 

分 类 号：TP206[自动化与计算机技术—检测技术与自动化装置]