Fast Waveform Analysis And Processing Techniques Of Digital Osciloscope

With frequency range of modern electronic signal continue to expand,increasing complexity and diversity,a new challenge is presented by three-dimensional oscilloscope’s real-time analysis and processing capabilities.With the existing conditions,how to promote real-time processing performance of digital three-dimensional oscilloscope become the new focus in the field.Generally,the domestic mid-range digital three-dimensional oscilloscope is constituted by FPGA+DSP,and waveform anaysis and processing functions is performed by DSP,but the data thoughput is small and the processing speed is low, therefore,the development of data acquisition system is restricted.Based on the above reasons,this paper studies the key technologies to reduce the time of waveform analysis and processing,major works in this paper are summarized as follows:1. The algorithm of extract and interpolation.This paper studies the relationship between sampling rate,extract and interpolation,and proves the necessity of extract and interpolationship.A design of the extraction is studied.By comparing the linear interpolation method and the sinusoidal interpolation method,interpolation algorithm is choosed based on multiphase interpolation filter.Finally,the software interpolation algorithm and hardware interpolation algorithm is used in the comparison,proved the efficiency of hardware interpolation algorithm is improved 9 times.2. Digital filter design method based on the FPGA.Firstly,the basic principle of FIR filter and window function design method are discussed,and the structure based on FPGA and design of FIR digital filter are researched.What’s more,this paper completes the design verification of digital filter module.And by the comparison of the DSP filter algorithm and the FPGA filter algorithm,the speed of filtering algorithm based on FPGA is proved,and the speed improves 323 times.3. The FFT algorithm based on FPGA.First,add a window on the signal,and then use the base 2 FFT algorithm to achieve 1024 points FFT calculation,the CORDIC algorithm are used to compute magnitudes.Verification results show that the speed of the FFT algorithm based on FPGA improved 473 times by comparing the FFT algorithm based on FPGA and DSP,and the time of the spectrum analysis of the oscilloscope are shorted effectively.4. Waveform parameter measurement method based on FPGA.There are some shortcomings using DSP measure waveform parameters,so a new parameter measurement method based on FPGA is discussed.And the design of parameter measurement is analyzed and verified,the result shows that parameters measurement method based on FPGA can effectively improve the measurement speed,and reduce parameter measurement time.