声光偏转多频信号同时探测互调现象研究  

Research on Phenomenon of Intermodulation in Detection of Multi-Frequency Signals Based on Acousto-Optic Deflection

作　　者：李小纳[1] 何宁[1] 邓德迎[1] 

机构地区：[1]桂林电子科技大学信息与通信学院,广西桂林541004

出　　处：《光学学报》2010年第9期2504-2507,共4页Acta Optica Sinica

基　　金：国家863计划(2007AA0860)资助课题

摘　　要：声光偏转效应可用于信号载频相关信息的测量。但当多个射频信号同时加载到声光偏转器时,在布拉格条件下信号间将发生互调现象,给信号检测带来很大的困难,尤其是三阶互调光束的干扰尤为严重。针对这种声光衍射产生的互调干扰,从声光衍射互作用原理出发,讨论了产生互调现象的条件、衍射分布和信号频谱图。通过理论分析,提出了减小互调现象的方法和措施。构建测试系统平台,对多路信号同时到达声光偏转器时产生互调干扰的程度进行了实验验证。在声光偏转器有效带宽内,衍射效率一定的情况下,通过适当控制射频驱动功率,保证声光偏转器工作在线性区域,可有效地减小互调干扰,从而有利于系统的信号检测。The measurements of the information on the carrier frequency can be realized by the acousto-optic deflection effects. However, when the multi-radio frequency signals are simultaneously input to the acousto-optic deflector, the intermodulation between the signals will be generated in the Bragg regime. It causes great difficulties to signal detecting, especially interference from the third-order intermodulation is particularly serious. In response to the intermodulation interference coming from the acousto-optic diffraction, the conditions of generating intermodulation, diffraction distribution, and frequency spectrum are discussed on the basis of the principle of the interaction of the acousto-optic diffraction. Through theoretical analysis, the methods and measures by which the phenomenon of the intermodulation can be reduced are proposed. In order to verify the degree of intermodulation interference in the detection of multi-frequency signals, a test system is constructed. By way of experimental analysis, the conclusion that the intermodulation interferences can be reduced effectively by controlling drive power of radio frequency （RF） properly to ensure that acousto-optic deflector works in linear regions is drawn, when diffraction efficiency in the effective bandwidth of acousto-optic deflector is fixed.

关 键 词：衍射 光栅 多频互调 线性驱动 带宽 

分 类 号：TN929[电子电信—通信与信息系统]