The Design And Realization Of High-speed Data Acquisition System Based On Equivalent Sampling

The most important method to get information is to use Data Acquisition System (DAS), which is the link between the outside and the computer. What's more, it is a significant way to get the information. In the recent year, as the development of technique in sensor and microelectronics area, data acquisition system has been using widely in civilian economy and the building of national defense fields, especially, the widespread of computer technique has built data acquisition technique a more extensive development perspectives.This paper has achieved the following work:(1)The project has completed the design of high speed data acquisition system. In the choice of high speed analog digital converter, we pick AD9480 which is 250MHz conversion rate and produced by ADI Co.2005; in the choice of the other operational amplifier, also choose the bandwidth as wider as possible. Besides, the ARM9 S3C2410 Samsung Co. and FPGA COLONEIII EP3C25 Altera Co. constitute a minimum system, instead of FIFO+MCU traditionally. The project use this structure to fulfill the sampling of signal acquisition, control, storage and display as the core of the control. Not only increase the integration, dependability, stability of the system but also reduce the complexity of designing PCB enormously by using this new structure. The debugs also prove the feasibility of this scheme.(2) In the practical application, the sampling signal frequency ought to achieve 5-10 times of the detected signal frequency. So, when we observe high frequency periodicity signal by the way of equivalent sampling methods. Using this method can tremendously broaden the testing area of the system as well as reduced the cost of high speed data acquisition system. In this paper, we use the narrowband generating circuit and time amplifying in dual slope integral to actualize Random Equivalent Sampling Theory, and describe the whole process of the design in detail.(3) The data acquisition system that described in this paper use AT056TN52 which is produced by Innolux Display Group Co. and 5.6 inch LCD display. We design the concision and aesthetic waveform display interface to accomplish the communication between users and hardware, that makes user face the data acquisition more directly. In the waveform display interface, in order to reduce the burden of user, we actualize the design of some functional modules, including the measurement of frequency, cycle and peak-peak value.This paper systemically investigates theory and method of Random Equivalent Sample and Interpolation in high speed data acquisition system. The experiment suggests that this system can sample the detected wave correctly and also complete the calculations, achieve the design request on the whole.