High-speed Data Acquisition System Design And Dynamic Parameter Acquisition Technology Research

With the wide application of data acquisition technology in the frontier fields of weapon development,medical equipment,satellite communication and so on,data acquisition system is developing towards high speed and high precision.At present,in the face of increasingly complex test environment,it is necessary to consider whether the dynamic performance of the system meets the test requirements.However,dynamic parameters are the key technical indicators to characterize the dynamic performance of the system.Therefore,before the practical application of the system,it is urgent to accurately obtain its dynamic parameters and evaluate the dynamic performance of the system.Based on the above background,this paper has carried out the following research :(1)The basic principles and design principles of the data acquisition system are studied to provide a theoretical basis for the design of the subsequent high-speed data acquisition system.At the same time,the basic theoretical research on the dynamic parameter acquisition method of the system is carried out,and the overall scheme of dynamic parameter acquisition is designed.(2)The key modules of the high-speed data acquisition system are optimized.By analyzing the decoupling capacitor equivalent model,the decoupling capacitor parallel circuit is designed,which effectively suppresses the power supply noise and realizes the optimal design of the power module.Then the sampling clock jitter is analyzed,the selection of high speed and low jitter clock chip is completed,and the optimal design of clock module is realized.At the same time,in order to improve the bandwidth and reduce the harmonic distortion,the differential coupling design of the analog signal input is completed.(3)Aiming at the problem that high noise test signal affects the acquisition of system dynamic parameters,an eighth-order Butterworth bandpass filter is designed to provide highperformance harmonic suppression,eliminate the noise and harmonics of the output signal of the signal generator,and ensure the accurate acquisition of system dynamic parameters.(4)Under the condition of incoherent sampling,a dynamic parameter acquisition algorithm based on Local mean decomposition(LMD)is proposed to solve the problem of spectrum leakage in the acquisition of system dynamic parameters.The algorithm first decomposes the non-coherent sinusoidal signal by LMD to obtain the product function component of the fundamental wave,and obtains the frequency of the fundamental wave.Secondly,the four parameters of the fundamental sinusoidal signal are obtained by parameter fitting method to realize the extraction of incoherent fundamental wave,and the test signal is reconstructed according to the coherent fundamental wave signal obtained by Nyquist theorem.Finally,fast Fourier transform is performed on the reconstructed test data.Simulation and experimental results show that the proposed method can effectively suppress spectrum leakage and achieve accurate acquisition of system dynamic parameters.