【摘要】 设计并演示一个可实现视音频信号同步无线传输的自由空间光通信系统。该系统包括信号发生、调制和接收模块。对由信号发生模块输出的视音频信号进行时分复用(TDM),复用信号以电信号形式作用于声光调制器(AOM)并将其加载于入射到AOM的激光束上,AOM输出调制光信号,最后接收模块还原出视音频信号。整个通信系统带宽为6.7 MHz,通过电-光-电转换过程,将时分复用和声光调制相结合实现了视音频信号同步无线传输。本系统针对具体工作环境,自建核心电路:时分复用/解复用电路和输出光端机电路,采用单片机调控输出信号质量。实验证明该系统具备成本低廉、实用性强和灵活性高等优点,为监控系统、应急通信等应用场合提供一种简易有效的视音频信号同步无线传输方案。更多还原

【Abstract】 A free-space optical( FSO) communication system with video and audio signals synchronous wireless transmission has been designed and demonstrated. The system consists of signal transmitter,modulator and receiver.The video and audio signals outputted from signal transmitter were transformed into multiplexer signal by means of the time-division multiplexer( TDM).The multiplexer signal was added to laser beam when it connected to the acousticoptical modulator( AOM) in the form of electric signal. The receiver was used to convert the light signal outputted from AOM into electric signal.The 3 d B bandwidth of the system is 6.7 MHz.Through the process of electric-light-electric conversion,the synchronous wireless transmission of video and audio signals was achieved with the combination of time-division multiplexing and acousto-optic modulation. The circuit of time-division multiplexer/de-multiplexer and photoelectric conversion circuit were built according to the specific work environment. The quality of the output signal was controlled and adjusted by a microcontroller.The experiments proves that the system has some advantages of flexibility,practicality and low cost.And it provides an efficient scheme of synchronous wireless transmission of video and audio signals for monitoring system and TV access network.更多还原