The Scheme Of Test System Of Visible Light Communication System And The Research Of Its Equalization Technology

In the recent five years,the Visible Light Communication has received more and more attention.The VLC is the use of visible light band spectrum as an information transmission carrier,in the air directly transmitted light signal,which do not need a cable transmission medium.This technology will be a combination of lighting function and communication function,in the future it will be achieved the local wireless Internet access with LED lights.With the development of technology research,in the VLC the application of equalization technology is becoming more and more important,the rate of the system has been improved.In the research of visible light communication system,the limited bandwidth of LED severely limits the rate of information transmission.To solve this problem,the thesis focuses on the research of the equalization technology.The work and innovation of this thesis about VLC are as follows:1.The design scheme of the VLC hardware circuit is improved on the basis of the original Ethernet switch chip,and then it is applied to the VLC.In the design,it not only need to be familiar with the communication process between the Ethernet physical layer,but also need to choose or change related functions according to the specific needs of VLC.In the hardware circuit,the matching of the internal time sequence is very important,in the case of high data rate,the digital clock synchronization determines the maximum data rate of the program.2.The structure of transversal filter is realized by analog circuit,using suitable delay lines and analog converter,LED frequency response is compensated,simulation results show that LED bandwidth can reach 150MHz,which is better to complete equalization,compared with the traditional analog circuit based equalization technology,there is no jitter,design flexibility and other advantages.3.In the visible light communication,the simulation of the fractional spaced equalizer is studied in this thesis,and a new type of 1+2+3/4 fractional spaced equalizer is proposed.Simulation results show that LED bandwidth can reach 120MHz,which is better to complete equalization.