The Study Of Real-time Data Acquisition System Based On USB2.0

Virtual instrument has shown a new tendency with the development of intelligent instrument. And in some measurement, data acquisition lasts long time and a great many data must be transferred to PC, which needs a new system to acquire data and save them in real time. So the author has studied and designed a new virtual instrument system of real-time data acquisition using USB2.0 technology, based on the new idea of virtual instrument and the demand for data acquisition in real time.The dissertation has given the designing details and the success in study, which includes general scheme, circuits, software and performance of real-time data acquisition system based USB2.0 technology. Firstly, the system has a good SNR and high accuracy, which is owed to wideband operational amplifier being used, accurate adjustment by DA, 12-bit high sampling AD converter being applied. Secondly, data transmission becomes less by using forecasting code technology and dictionary compress technology, which are run by DSP on board. Thirdly, the system can transfer data to PC at a high speed on the series interface based on USB2.0 technology, which is satisfied with the demand for a great many data transmission. In addition, control core is designed with large-scale-integrated FPGA chip, which decreases the designing complexity, enhances the system stability and lessen the instrument volume.The system has been tested, and its performance is stable and reliable. The study of it, achieves that a new type of sea data acquisition instrument has been produced with the technology all above, which has new characters of high function-price-ratio, powerful function, low power supply and easily using.