Development Of PXI Express High-speed A/D Module

High speed data acquisition technology is widely used in communications,radar, testing and other fields.Together with sensor technology, signal processingtechnology, and computer technology, high speed data acquisition technologyconstitute the foundation of modern detection techniques. With the rapid increase indata acquisition rate, a higher data transmission rate is required. PCI Express is thethird generation of computer I/O bus. As an expansion of PCI Express in theinstrument field, PXI Express is able to provide flexible bandwidth configuration forinstruments.Based on the data acquisition module technical indicators, a detailed needsanalysis is presented and a overall plan of the hardware design is made. Based onthe plan, a PXI Express high speed AD module is developed. The module use aFPGA chip with PCI Express hard IP core to design PXI Express interface. In thedesign of analog channel, signal amplification/attenuation,AC/DC coupling,inputimpedance transformation circuit are implemented. To meet the high-speed dataacquisition needs for large-capacity cache, a DDR2memory circuit is designed,making the cache depth up to1GB. In the design of FPGA circuit,Cadence FSP toolsis used to optimize pin assignments, which can reduce the pin cross.In order to achieve a clear hierarchy of the logic and make the logic easy tomaintain and upgrade, the Qsys design flow is introduced into FPGA logic design.By using the IP core in the design of logic,the logic reusability is improved. In orderto reduce the volume occupied by the sampling data, accelerate the datatransmission efficiency, a data compression IP core is designed to compress thesampling data. In software design, a VPP specification compatible driver is designedby using the VISA programming interface.The PC applications is designed byLabWindows CVI.Finally, comprehensive testing and performance analysis are conducted.Testing results show that functionality and technical indicators of the PXI Expresshigh speed AD module meet the design requirements.