| According to the 11th 5-Year-Plan on seismic data acquisition, the high real-time capability is required by the self-designed new system. Increasing the transmission speed and reliability is the key technology in the new system. This paper is developed around the characteristics of data transmission between DAUs in the new system with the purpose of increasing the transmission speed and reliability, and the researches on modulation-coding related technology and its application in seismic data transmission is presented. The main contents of the paper are as follows:Research the characteristics of baseband transmission on the system, analyze the reason for the errors in data transmission, and establish mathematical model for the actual channel. Analyze the effects of ISI on data transmission. Research the relationship among run-length and bit-rate and data-rate based on the established channel model, and provide a solid theoretical foundation for the system's modulation-coding method design.Analyze the system's actual channel constraints. Compare the performance of different modulation-coding method and determine the final method for the system. Implement the 8B/10B encoder and decoder. Against the low code-rate of 8B/10B code, the 9B/10B code with higher code-rate is proposed and its feasibility is analyzed.Design and implement the 9B/10B modulation-coding method, including: design the 9B/10B code map, simplify the 9B/10B code map, implement the 9B/10B encoder and decoder, and analyze the performance of 9B/10B code. The 9B/10B code has the advantages of DC-free and run-length-limited which are able to meet the data transmission requirement of the actual channel.The 9B/10B modulation-coding method is tested on the DAU hardware platform. By comparing the test result between 8B/10 code and 9B/10B code, the feasibility and applicability of 9B/10B modulation-coding method for increasing the transmission speed and reliability is verified. |
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