Virtual Spectrum Analyzer Based On DSP Technology And PCI Bus

Virtual Instrument has become an important direction of instrument development, now it has been widely used in many fields. FFT analysis is a widely used method in mechanical engineering, fault detection and many other fields. However, the traditional FFT analyzer is expensive and is not easy to be upgraded. The birth of virtual FFT Spectrum Analyzer gets rid of the limitation of traditional FFT analyzer, and paves the way for the application of FFT analyzer. The uses of DSP technology make the future broadened of Virtual Instrument. This article, based on the deep study of DSP system, designed a virtual FFT Spectrum analyzer based on DSP technology. The design is new and of great practicality, which indicates the importance of Virtual Instrument in the development of instruments.The signals are all processed by computer system in the Virtual FFT analyzer based on ordinary data acquisition card, which leads to lowering the real time quality in high-speed, multi-channel data processing, and even leads to user's unbearable waiting. To adopt DSP(digital signal processor) chips on the data acquisition card can improve real time quality and accuracy of data processing. While the digital signal processor relying on its particular hardware and instruction architecture 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.In condition of high-speed, real time data processing, the transferring speed determines real time quality in great degree. PCI local bus is the fastest local bus nowadays. And it has the excellences such as bust 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.According to the study target, this article developed a data acquisition card used as FFT spectrum analyzer based on DSP and PCI bus technology. The paper describes in detail the design scheme of hardware and the capability it reaches .The software of the system is composed of DSP program, the device driver and application program. The paper introduces the main DSP program and the DMA interrupt service program in single channel and multi-channel modes, also it describes the design of PCI device driver.Finally, some working examples of the system are provided.