Design Of Eight-Channel Parallel Isolation A/D Module Based On VXIbus

This thesis designed an eight-channel parallel data acquisition module based on VXIbus, which is a fundamental module to set up a VXI test system. On the bases of the thorough comprehension to the VXIbus specification and the multi-channel data acquisition system, and the deeply study to the basic principle and development trend of the VXIbus data acquisition technology, the eight-channel parallel data acquisition module is developed. The main contributions of the thesis are as following.Firstly, the overall design scheme of the eight-channel parallel data acquisition module is determined. FPGA is chosen as the core logic control. The serial A/D transformation and the channel isolation technology are adopted. Eight -channel parallel data acquisition and test data time-sharing storage are realized. Verilog HDL (Hardware description language) is adopted to design the VXI register-based interface circuit and control circuit of each channel. Secondly, the dynamic storage module designed by our institute is used to design the buffer of the module,, which provids the mass storage space for data acquisition, simplifies the design of circuit board and control circuit of the module, meanwhile, provides the solution to the application of huge capacity continuous acquisition.Thirdly, the range switch circuit and filter circuit are designed in the analog input channel. To realize the safe high speed acquisition, the interface circuits are separated from the function circuits, and the isolation power with high performance and digital isolator is used to restrain the common mode disturb and noise of the input.Fourthly, the trigger circuit is implemented, supporting software trigger, channel trigger, bus trigger and multi-channel synchronous trigger. According to the characteristics of the signal under testing, the user can configure the sampling rate and range. Besides, different A/D channels can work under different sampling rates and ranges.Finally, in the software design of the module, VISA is used to develop the driver, and the software panel compliant to VPP specifications is developed...