| DAQ(Data AcQuisition) system has been widely used in the field of industrial control&testing and signal processing. The complexity of testing environment and the intrinsic nature of signals have always been the major concerns in DAQ system designing. In most traditional multi-channel DAQ systems, it could easily be noticed that not only all the input channels must be in working state when the device is on, but they also have to work in the same sampling frequecey at a time. However, this is not the case in many situations, although one had to admit it is a very convenient way of designing. Sometimes, when the input signals are in different frequency domains, or the number of actual signal signals is less than the total number input channels provided by the DAQ system, there could be a great waste of system resource due to the limited input bandwidth. This article comes up a noval method of eliminating the defects of traditional DAQ system. The DAQ system discussed in this paper could sample signals in different frequency domain at a time, and could also be configured to accommodate input channels according to actual situation. With these characteristics, this DAQ system could maximize the usability of the input bandwidth and is suitable for most data acquisition cases.The DAQ system discussed in this paper is brought up by an ongoing project, and system flexibility is the main focus. The background and the current status of the project have been discussed in the first chapter. In chapter two, the hardware schematic and the devices used have been generally introduced. Chapter three mainly focus on CPLD programming and its internal module designing. The essences of this paper:"the preepmitive channel scaning algorithm"has been thoroughly covered in this section. After that, how to develop a PCI device driver on Windows system is dicussed in the next chatpter. In the end, system debugging and testing is applied to evaluate the overall performance of the DAQ system. |
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