红外语音通信系统的研究与设计

发布时间：2018-11-15 06:59

【摘要】：个人移动通信和多媒体业务量的增加,使通信技术朝着系统宽带化、灵活性的方向发展。无线光通信结合了光纤通信的高带宽和射频无线通信的灵活性优点,更适应现代通信技术的发展。红外语音通信属于室内无线光通信研究的范畴,由于其发射角度的和传输距离的限制,能够更好的防止被监听,具有更好的安全性,且系统结构简单,成本低,实际应用价值更高。但红外语音通信系统的发射器功率限制了其信息传输的距离,因此红外语音通信多用于点对点的视距通信中。因此本文主要研究重点为视距范围内的室内红外语音通信系统,由以下几个方面组成:首先,根据国内外参考文献对所研究课题进行总结,其中包括红外语音通信系统的研究背景、红外无线通信技术相比较射频通信的优势,国内外红外语音通信系统现阶段研究的状态、红外语音通信系统的发展趋势等方面,该部分主要建立在以往阅读文献的基础上,对所研究的领域有了较全面的认识,为本课题研究打下基础。其次,提出红外语音通信系统的基本模型,由于红外光的不可见性,稳重采用辐射度学对红外辐射进行研究,引出了几种常见的红外辐射量;红外发光管和接收管的研究是红外语音通信系统设计的关键,这部分对红外的光学器件进行了分析,在此基础上选出了适合红外语音通信系统设计的器件。再次,从红外无线通信的强度检测/直接接收系统(IM/DD)模型得出衡量红外无线通信信道的性能指标:系统脉冲响应。结合红外光辐射理论,对红外无线通信发射器、接收器传输功率和通信信道进行研究,建立红外通信信道的数学模型,从理论上详细介绍了系统的脉冲响应计算方法,并利用matlab实现对脉冲响应进行仿真,通过改变仿真参数分析红外无线传输中的各项指标对系统性能的影响,研究结果表明:红外发射器发出的红外光脉冲经过反射后到达接收器会产生多径效应,脉冲响应随着反射次数的增加呈下降趋势。但在室内传输过程中,由于传输距离只有10米左右,受多径衰落的影响不大,可以利用红外光的反射特性,增加中继设备,提高红外语音通信系统的灵活性,提高系统的传输距离。最后,从系统的整体设计入手,完成红外语音通信系统各个功能模块的设计。阐述了红外语音通信系统进行脉冲调制的必要性,给出了几种常用的脉冲调制方式的概念,结合传统红外语音通信的设计经验,选用PWM调制作为红外语音通信系统的调制方式。根据D类音频放大器的基本原理和采样定理等相关理论,确定了红外语音系统的各个功能模块的参数,采用大功率的红外发光二极管和中继电路来增加红外语音通信系统的传输距离,最终完成了红外语音通信系统的设计。本文的重点在第四章红外语音通信系统的设计部分。
[Abstract]:With the increase of personal mobile communication and multimedia traffic, communication technology develops towards the direction of system broadband and flexibility. Wireless optical communication combines the advantages of high bandwidth of optical fiber communication and flexibility of radio frequency wireless communication, so it is more suitable for the development of modern communication technology. Infrared speech communication belongs to the research field of indoor wireless optical communication. Because of the limitation of its transmitting angle and transmission distance, it can better prevent being monitored, have better security, and the system structure is simple and the cost is low. The practical application value is higher. However, the transmitter power of the infrared speech communication system limits the distance of its information transmission, so the infrared speech communication is mostly used in point-to-point line-of-sight communication. Therefore, this paper mainly focuses on the indoor infrared speech communication system in the range of sight, which is composed of the following aspects: firstly, according to the domestic and foreign references, the research topics are summarized. It includes the research background of the infrared speech communication system, the advantages of the infrared wireless communication technology compared with the radio frequency communication, the current research status of the infrared voice communication system at home and abroad, the development trend of the infrared voice communication system, etc. This part is mainly based on the previous reading literature, and has a more comprehensive understanding of the field of study, which lays a foundation for the research of this subject. Secondly, the basic model of infrared speech communication system is put forward. Due to the invisibility of infrared light, infrared radiation is studied by using radiance and several kinds of infrared radiation are introduced. The research of infrared luminous tube and receiver is the key to the design of infrared speech communication system. In this part, the optical devices of infrared are analyzed, and the devices suitable for the design of infrared speech communication system are selected. Thirdly, from the intensity detection / direct receiving system (IM/DD) model of infrared wireless communication, the performance index of infrared wireless communication channel is obtained: system impulse response. Combined with infrared radiation theory, the transmission power and communication channel of infrared wireless communication transmitter and receiver are studied, the mathematical model of infrared communication channel is established, and the calculation method of system pulse response is introduced in detail theoretically. The pulse response is simulated by using matlab. By changing the simulation parameters, the influence of various indexes in infrared wireless transmission on the performance of the system is analyzed. The results show that the infrared light pulse emitted by the infrared emitter will produce multipath effect after it reaches the receiver, and the pulse response will decrease with the increase of the reflection times. However, in the process of indoor transmission, the transmission distance is only about 10 meters, which is not affected by multipath fading, so we can use the reflection characteristic of infrared light to increase the relay equipment and improve the flexibility of the infrared voice communication system. Improve the transmission distance of the system. Finally, starting with the overall design of the system, the design of each functional module of the infrared voice communication system is completed. This paper expounds the necessity of pulse modulation in infrared speech communication system, and gives the concepts of several common pulse modulation methods. Combined with the design experience of traditional infrared speech communication, PWM modulation is selected as the modulation mode of infrared speech communication system. According to the basic principle of class D audio amplifier and relevant theories such as sampling theorem, the parameters of each functional module of infrared speech system are determined. High power infrared light-emitting diode and relay circuit are used to increase the transmission distance of the infrared speech communication system. Finally, the design of the infrared voice communication system is completed. This paper focuses on the fourth chapter of the design of infrared voice communication system.
【学位授予单位】：延安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.1

【参考文献】