Development Of Wake Signal DAQ System Based On LABVIEW And USB Interface

The USB interface data acquisition(DAQ) product on the market at present exists disadvantages of low accuracy,low sampling rate, low speed of data transmission,so they are inappropriate in the laboratory project involved, to the detriment of the weak signal acquisition task. The data collection of high-end products at home and abroad for expensive and low utilization ratio of subject, so they are adverse also for formed for production force. In view of these situations, designed a set of low noise data acquisition system.The data acquisition system includes three parts. Respectively is weak signal processing circuit module, DAQ module and PC applications module. Through the conditioning circuit, weak signal which can not enter the data collection process directly is conditioned to normal signal.Using USB bus technology to transmitting data, it is convenient and it can ensure the data transfer rate. Adopt virtual instrument software LABVIEW to design host application software, used in real-time display, analysis and processing data. The DAQ board selects High-speed differential amplifier AD8132 for further preamplification.Using CPLD and external SRAM, put "Ping-pong algorithm" in data stream to compose a large capacity FIFO data buffer system,reduce the system cost in the premise of not reduce the system performance. Introducing WDM driver model,adopt USB2.0 bus technology for data transmission, CPLD system as external host controls USB chip for slave FIFO mode transmission,to ensure the data transmission rate.And because the characteristics of convenient and hot swaps of USB interface, The system can be convenient for further electromagnetic shielding measures.Adopt independent clock to provide precise synchronous clock signal for CPLD and AD converter, so as to reduce the clock phase noise.Test results show that, The data acquisition system have advantages of low noise, transmission speed, high precision and low cost,Develop a system which is a collection of weak signal acquisition, processing,and display.Can be used in weak signal collection in the projects.