Design And Implementation Of A Type Of PAM4 BERT

Optical communication technology is an information transmission technology based on light.Because of its low transmission loss,large information capacity and fast transmission rate,it is becoming the core strength of communication technology.With the further increase of the transmission rate,the high-speed optical communication system may generate errors due to problems such as attenuation and dispersion.How to accurately and effectively measure the bit error rate of each module of the optical system,thereby guiding people to improve the performance of the optical system.High-performance error testers have also become an important research target in the field of communication measurement.In order to meet the error test requirements of optical modules operating at different speeds,A new type of PAM4 BERT was designed and developed.It supports most common test rates in various environments from 1.25 Gbps to 56.25 Gbps,supports a variety of NRZ and PAM4 patterns and custom pattern output,and supports control on the PC side through the host computer,provides accurate testing for a wide range of optical modules in network environments such as Ethernet,SONET,OTN,Fibre Channel,CPRI and Infiniband.The content of this paper mainly covers the following three aspects:(1)Analyze the process and cause of the error code in the optical communication system,summarize the working principle of the error code test system,explain the common test patterns,and then select the optimal design through comparison,and put forward BERT performance requirements.(2)Draw the block diagram of the hardware platform of the PAM4 BERT,divide each unit circuit according to the function,complete the selection of the main device of the unit circuit and the overall schematic design,perform the impedance matching calculation of the high-speed circuit and complete the high-speed PCB simulation design.(3)According to the error test workflow,write the system MCU program and the host computer program,realize error test function and the remote-control test function of the host computer.