Data Acquisition And Processing System Based On DSP Technology And PCI Bus

Data acquisition card is the AD interface card, which converts the analogy signal to the digital signal, and transfers the digital signal to the computer. The function of the traditional acquisition card is limited in data acquisition, and the task for processing the data is finished by the computer, which leads to the reducing of the real time quality and even user's long time waiting. The paper designs a data acquisition and processing system which breaks through the only function of sampling data of the traditional acquisition card, and realizes processing data on card. Furthermore, by designing the system's hardware and software creatively, when working in one-channel mode, the system realizes real time sampling in both time domain and frequency domain, that is to say, the card can provide time and frequency information to computer without losing any point of the signal for long time.The data acquisition and processing system should not only convert the analogy signal to the digital signal, but also realize the specifically digital processing arithmetic expected by the user. The digital signal processor becomes the preferred utility for realizing digital arithmetic rapidly and precisely relying on its particular hardware and instruction architecture. The paper introduces the CPU structure,Memory composition,Peripheral resources and the addressing modes of DSP, and interprets why it is fit for realizing digital signal processing arithmetic. The high- speed data acquisition and processing system requires not only fast and precise digital signal processing ability but also high data transmission bandwidth, or the system's real time property will decrease significantly. The interface used by the system is the primal factor for determining the transmission bandwidth. PCI local bus is the fastest local bus nowadays. And it has the excellences such as burst transfers,little storing delay, working independently with CPU and the high compatibility. Using the PCI interface between the data acquisition system and the computer can satisfy this system's transmission bandwidth. The paper introduces the characteristics of the PCI bus and the performance promotion when the data acquisition system using PCI interface, along with the great convenience it brings about.Based on the DSP and PCI technologies, the paper designs a data acquisition and processing system independently, which consists of input passage module, sampling and processing module and computer interface module. Each module is composed of some electronic components, and the paper has made detailed hardware designing for each module.The software of the system is composed of DSP program and the device driver. The paper introduces the main DSP program and the DMA and INT1 interrupt serviceprogram for system's one-channel and multi-channel working modes. The system's device driver is designed using the Microsoft's device driver kits.Finally, some working examples of the system are provided.