光电混合反馈二维激光多普勒测速仪研究

Two Component LDA with Optic一Electro一Hybrid Feedback

本文首次提出利用光电混合反馈激光多普勒测速仪的中频频率区分二维速度分量的方法，研制了一种光电混合反馈二维激光测速仪。与现有仪器相比，它具有信号分离简单、信噪比高和动态测量范围宽等特点。文中介绍了该仪器的构成和工作原理，分析了光电流信号的频谱特性和信号分离方法，最后给出了该仪器用于二维流场测量的实验结果。

Abstract A two一component laser Doppler anemometer(LDA)witoptic一electro一hybrid feedbackis described. Two component signals are distinguished by means of the dif-ferent intermediate frequencies of two closed一loops containing both optical and electric sig-nals, and separated simply by narrow一band fiIters from the output of one detector, The im-portant features of the two一component LDA are simple optics , high signal一to一noise ratio-and wide dynamic range. The principle and set一up of this instrument are introduced , andthe spectra of photo一current signals and their separation are discussed in this paper. Theapplication of this instrument in turbulent flow measurements is also presented.