Design Of Virtual Oscillograph Based On USB

Virtual instrument (VI) is a new electronic instrument that is combined with electronic measure technology and computer technology . It has good outlook. The aim of this paper is to design a Virtual Oscillograph (VO) based on the USB Interface technology. It is not only a virtual test Instrument, but also a peripheral of computers. Together with computers, the instrument can construct a powerful test system.Begin of the paper, introduced the Virtual instrument's actuality and outlook, explained the paper's abroad appliance outlook. And system analysed the design's function then brought forward primary performance targets. In follow sections, detailed explained every part's function and realized means. This chapter mainly introduces the following parts, the first is about analog signal process, which starts with instrument security and accuracy requirements, introduces analog signal process circuit before AD converter. The second introduces controlling logic of data collection card, which is the emphases and difficulty of the whole design. The realization of function mainly basis onCPLD. The mainly function is to control process of date collection, including the collection and save of date, the realization of trigger logic and interface with MCU. The third part introduces the interface between date collection card and computer communication. In this design, the writer uses USB interface. In advance, simply introduce USB. Following, introduce concrete circuit and programmer design of MCU. Finally, introduce anti-disturb design of system. In the whole design, the writer mainly works on system layout and harmonize of each parts. Beside, the writer designs independently circuit of this instrument, including programming of CPLD and MCU, and designing of communication protocol with computer. The appendices list form of the instrument and control panel of computer.