Research On The Data Processing Method Of Oscilloscope And Its Realization Of Logic Cicuit

Overview the development of the oscilloscope,there are more and more functions which implemented in oscilloscope.Therefore,the data processing technique of oscilloscope is becoming more and more complex and diversified,and this situation proposes higher requirements for the data processing theory and methods of oscilloscope.According to this change,many high-end oscilloscope manufactures are actively involved in the data processing technique of oscilloscope,at the same time,the development of FPGA technology makes the data processing technique freed from the pure software algorithms,furthermore,the data processing algorithm implemented in FPGA can significantly improved the refresh rate of waveform.This thesis takes the PXI bus oscilloscope module as platform,firstly researches the data processing technology of oscilloscope,such as trigger synchronization,hardware interpolation,bandwidth flatness compensation and so on,and then gives performance analysis;secondly,considers the performance constraints of each module from the gradation of data processing of oscilloscope,we can reasonably configure and optimize the system structure to obtain the performance balance between modules and the optimization of the system performance.Finally,makes detailed analysis for the waveform generated by the oscilloscope and then gives the test results.The main research contents are as follows:1.Digital trigger synchronization is studied.Due to the use of multi-core or multi-chip ADCs in high-sampling oscilloscope,high-speed data stream deserialization makes one data-output clock correspond to multiple sampling data,causing the signal appearing digital spurs and pixels jitter.In order to solve this problem,this thesis uses FPGA phase control technology and external triggering deserialization sampling circuit to achieve phase alignment of ADC data and a one-to-one correspondence between sampling points and trigger points,thereby improves the display effect of waveform and the accuracy of digital trigger synchronization.2.Hardware interpolation technique is learned.This thesis firstly compares several typical interpolation algorithms,and selects linear interpolation and sine interpolation as the commonly used interpolation methods in the oscilloscope for hardware implementation.Secondly analyzes the influence of the key parameters oflow-pass filter on the filter performance after interpolation,and then realizes the design of the low-pass filter.Finally,through the MATLAB and Model-Sim simulation and the thesis' s actual platform verification test,the hardware interpolation effect meets the requirements of this subject.3.Bandwidth flatness compensation technology is implemented.This article creatively proposes a digital compensation filter design technique to improve the oscilloscope's bandwidth flatness specification.Firstly,two methods for obtaining the oscilloscope channel amplitude-frequency characteristics are compared,choosing the frequency-sweeping method to obtain the design parameters of the compensated filter.Secondly,the influence of the key parameters of the compensation filter on the performance is analyzed in detail.Based on this situation,this thesis proposes a method of correction filter amplitude matrix to reduce the filter's order.Finally the result shows that the digital compensation oscilloscope can solve the problem of none-flatness channel bandwidth,at the same time,it can make the bandwidth index meet the requirements of the subject.