Design Of Data Acquisition And Processing System Based On USB

Data acquisition and processing system is widely used in scientific researchand industry field. DFT cannot be directly used to harmonic analysis of periodsignals, this paper discussed its limitation? presented a window and interpolationmethod and designed a data acquisition system base on USB, with the measuringsystem of precision centrifuge's dynamic balance system as the background.The leakage of DFT is difficult to avoid due to unsynchronized sample, evenif the phase locked technique was used. Usually there are two ways to reduceerrors, the errors created by leakage are eliminated by windowing the signals, theerrors caused by picket fence effects are reduced by interpolation. This paperdiscussed the essential of the leakage phenomenon of DFT, deduced the formulasof window and interpolation algorithm and given a detail about Blackmanwindow, the simulation demonstrate the validity of this algorithm.Due to the speed and difficulty of installment the further development andapplication of data acquisition instruments were confined by the traditionalcommunication ways. As a good solution to these problems, USB technology iswidely used because of the feathers of hotplugging,plugandplay,easy toexpand, engrossing less system resource. The system in this paper is based onUSB interface. The paper involved many aspects about development of USBinstruments,including the design of hardware of USB interface, firmware anddriver based on WDM.Finally hardware and soft ware are debugged, and illustrate the installingprocedure of USB device, the control signal of A/D is analyzed emphatically, andthe realtimeand statistical performance of the algorithm of window andinterpolation is analyzed, and the validity and the feasibility of this algorithm isanalyzed by the acquired data.