Design Of Digital Storage Oscilloscope Based On LXI

With the development and innovation of instrument bus and automatic testing system, LXI bus technology was normed and proposed from VXI bus by LXI union. LXI is a testing bus based on network technology. With the rapid development of network technology, the testing system based on LXI interface has a broad development space and competitive potential.This paper introduces related content, standards and the development situation at home and abroad of LXI bus technology, analyzes the characteristics and advantages of LXI bus, and stresses the importance and necessity of the development of measuring instruments based on LXI bus. The realization of a digital storage oscilloscope based on LXI interface is emphatically discussed. The oscilloscope has two input channels, 100MHz analog bandwidth, 250MSPS sampling rate, eight bit vertical resolution, and multiple trigger functions.Design of the analog channel including the attenuation circuit, amplifier circuit, trigger circuit, and frequency measurement circuit is introduced in this paper. The anti-jamming design of the input channel is analyzed as well. Then, this paper describes how to achieve high-speed and large-capacity data acquisition, including the realization of the interface between high-speed parallel A/D converter and FPGA, as well as the interface between FPGA and SDRAM. And how to store high-speed data streams to SDRAM through the buffer is emphasized. The way to design a network interface system based on ARM9 is described as well as how to set up a cross-compiler environment to transplant Linux system to ARM9, and how to programme in Linux system to achieve the function of LXI interface is specified. Finally, how to achieve the control and various functions of oscilloscope by LabWindows/CVI in computer and how to establish network server to realize the network communication based on TCP/IP protocol through network interface with ARM9 are fully introduced.The oscilloscope module is the most basic and usual testing module of the LXI bus testing system, and its research will greatly promote the development of the LXI bus technology.