The Application Of Digital Signal Processing In Virtual Oscillograph

Virtual Oscillograph is main developing direction of oscillograph in the present stage. It adopts modularization, principal and subordinate parallel structure. High speed, Real-time, multi-function and portability are its characteristics. Its basic function is to finish Data Acquisition, singal analysis and signal processing.At present, the speed of acquitting data already has reach above 100 MSa/s in Data Acquisition circuit card of the Virtual Oscillograph. But the transmission-data speed of various kinds of communication interface are varied from several Kb/s to hundreds of Mb/s. Higher transmission speed of the communication interface is, more difficult and complicated are its design and application. This restricts real-time data transmission. Using the technology of the Digital Signal Proccessing, this thesis discusses the method of compression of the sampling data, so that it can reduce the number of transmission data and solve the problem that the speed of communication is not match the speed of sampling. The experiment platform of the system is the Data Acquisition circuit card based on DSP processor TMS320VC5409 chip.On the thesis, the author summarizes Virtual Instrument, Virtual Oscillograph and the system of Data Acquisition and introduces the study background , signification and the study task in the first chaper. The second chaper discusses the theory of datacompression——Discrete Fourier Transform (DFT) and Fast Fourier Transform (FFT) italso analyses the problem and the methods of solving them when we use DFT and FFT in practice.The next chaper introduces design of the hardware of the data acquisition system. It focuses on the application system of DSP and the communication interface between DSP and PC . In the fourth chaper, the author firstly narrates the software's integrateddevelopment environment——CCS, then design the soft of communication interface,implement the compression of the sampling data in DSP lastly. The focus of this chaper is how to realize compression and process of sampling data in DSP. The last chaper introduces summarization and view of the thesis.