Design And Realization Of Multiple Signals Optical Terminal

With the continuous development of social information process, people areincreasingly dependent on communication. Optical fiber communication based onoptical fiber as a transmission medium of communication, high speed, low loss, largecapacity communication, confidentiality, and in recent years has made rapiddevelopment. Optical terminal as a terminal device in optical communication systems,and the main function is to photoelectric conversion and data transmission. It haswide application in the field of telecommunications, surveillance, industrial control,video transmission.The main subject of applications in the field emergency communicationsoccasions, central station and slave station can have fast networking features. As faras possible using the least fiber, it would transmit unidirectionally three dedicatedsignals，and transmit bidirectionally the three RS-422signals and a voice signal. Themain work of this subject is how to solve to the forefront jitter rms value of threededicated signals, which is not greater than4ns, and is how to multiplex effectivelymultiple signals. In this paper, different implementation schemes were thoroughlyanalyzed, and the transmission link insertion loss was estimated.At last,2.5Ghigh-speed optical modules were used to transmit three dedicated signals, andlow-speed optical modules were used to transmit three RS-422signals and a voicesignal. Three dedicated signals are first sampled by high frequency, and then afterhigh-speed multiplexer and2.5G optical modules, and it is solved that the forefrontjitter rms value of three dedicated signals which is not greater than4ns problem. Forthe three RS-422signals and a voice signal, they are selected the appropriate framestructure, and sampled to become the synchronization signals, and then afterlow-speed digital multiplexers and low-speed optical modules, and were solved theproblem of multi-channel signal transmission. In addition, it is used the CPLDprogrammable logic devices to finish three dedicated signals sort after the high-speedtap, and to multiplex and tap about three RS-422signals and a voice signal. Finally, itwas debugged and tested the various parts of the system.The test results showed that the design of the subject of the optical terminal was stable, good effect of real-time transmission, and high flexibility, and meet the designrequirements, and proved the correctness and feasibility of the program.