The Research And Realization Of Digital Storage Oscilloscope System Based On VI Theory

With the rapid development of computer technology and introduction of virtual technology, a new concept "virtual instrument" was formed in the field of traditional instrument industry in the end of the 80s. Actually, virtual instrument is an automatic measuring and testing instrumentation system based on computer. General computer and functional hardware module were integrated by application software to provide the hardware support for realization of different functions of measurement needed by practical users, and users can operate the computer on the friendly interface of instrument panel to process the task acted on the tested signal, such as sampling, analysis, display and storage, as if all this work is finished on a instrument with the function designed and defined by the user. As the integration of computer technology and modern instrument technology, virtual instrument make the revolutionary breakthrough in the measuring theory and technique of the conventional instrument.By absorbing the theory of virtual instrument, a multipurpose virtual digital storage oscilloscope system is developed successfully. The software part of system includes the program of upper computer and the program of LCD's driving and controlling. Based on the graphic technology, the program of upper computer fulfills the virtual instrument operation panel on the screen of PC and provides a graphic interface with powerful function and easy operation. MPU and SED1335 drive and control the LCD tc work properly. And the controlling program of LCD runs in MPU to realize a simpler controlling interface on the LCD with the practical function.The hardware of system is the data acquisition equipment (DAQ), DAQ includes three main functional modules: FPGA, analog sampling and LCD controlling. With the exist of FPGA chip EP1K30TC144-3, several hardware functions are realized in the chip, such as sample controlling logic, FIFO inside, the connection circuit with PC, the connection circuit with MPU, the connection circuit with keyboard. Being the controller, the exchanger and the buffer, FPGA is the core part of DAQ and participates the realization of all functional modules of the system.The system is composed complicatedly in function so that several kinds of software and hardware techniques are adopted in the development, such as VHDLused to developing FPGA module in MAXPLUS, VISUAL C++ used to developing VI operation panel program, C51 language used to realizing the controlling and the driving of LCD, Protel 99 used to designing the circuit board of DAQ.The whole system has a lot of advantages, including proper structure, high integration, easy assembling and good performance. Designed to work at 40MHz the system can meet the requirements of teaching experiment and practical project completely. Generally, as DAQ working with PC, the system make full use of the resources of computer and show the merits of virtual instrument fully. At the same time DAQ and LCD will form a complete portable digital storage oscilloscope, which can process the proper measurement in the field.