Research On The Ami Manchester Decoding System Based On FPGA And USB

The petroleum industry is significant to the people’s livelihood, and oil well logging is the key to oil production. The oil well logging technology includes data acquisition, data processing and interpretation techniques, as well as the geological application techniques. According to a single factors of the oil well logging instrument at present, low test efficiency, poor functionality, low compatibility and so on, based on the requirements of the oil well logging, the modern data collection techniques, the data processing and interpretation techniques, also under the application of AMI(Alternative Mark Inversion) in Gas Holdup Logging System, this paper design a AMI Manchester decoding system based on FPGA and USB.Firstly, according to the drawback of the oil well logging data acquisition card, a high-speed real-time FPGA and USB data acquisition is researched. Under the design philosophy of high-speed real-time data acquisition card, the ping-pong buffer unit is based on the SDRAM and asynchronous FIFO, and an interface controller is designed according to FPGA and USB. Further, the hardware circuit of high speed real time data acquisition card is schemed out, which includes preprocessing module design, AD converter module design, ping-pong buffer unit module design, USB communication module design and power and reset module design.Secondly, according to the inflexibility and inaccuracy of the Manchester decoding software, AMI Manchester decoding software is designed. On the basis of AMI Manchester decoding software design ideas, a feasible design scheme is put forward, and the overall framework of AMI Manchester decoding software is designed. A detailed analysis and design is carried out respectively for the real-time data acquisition and processing multithreading-program, AMI Manchester decoding process, fiber probe gas holdup estimation procedures and Manchester data storage display playback program.Finally, a corresponding test platform is built to test the hardware and the software parts of the system. We use the USB Data Streamer software from Cypress Corp to test the transmission speed of the high-speed real-time data acquisition card. After that, we use the black box testing and the platform of Gas Holdup Logging System to test fiber optic signal acquisition mode, optical data storage mode and fiber optic data playback mode, to verify the feasibility and correctness of the decoding system.