| In recent years,due to the limitation of integrated circuit manufacturing technology,it is difficult to improve the sampling rate of monolithic ADC.To solve this problem,the technology of time-interleaved analog to digital converter(TIADC)is proposed.TIADC technology uses the method of M channels ADC parallel alternating sampling to realize the increase of sampling rate by M times.However,in practice,the ADC of each channel of the TIADC sampling system is different,which brings offset error,gain error and time error to the system,and ultimately leads to the degradation of the performance of the sampling system.Therefore,in order to improve the performance of the TIADC sampling system,it is necessary to calibrate these three mismatching errors.AXIe bus stands out among many automatic test system bus standards due to its advantages of fast transmission speed,strong compatibility,large power and strong heat dissipation.The automatic test system combined with AXIe and TIADC technology can achieve high sampling rate and fast data transmission rate.The upper computer software is an important part of the automatic test system.Therefore,this paper designs the upper computer software of high-speed data acquisition system based on TIADC.The specific research content of this paper is as follows:1.The basic principle of TIADC sampling system,the main sources of mismatching errors and the influence of mismatching errors on the performance of the sampling system are studied.The influence of mismatching errors on frequency domain characteristics and signal to noise and distortion ratio of TIADC sampling system is studied.2.The calibration method of mismatching errors is studied.Aiming at the defect that the cumulative average method and the average power method are not suitable for the input signal with DC component,an improved offset and gain error calibration method is designed.The improved calibration method is verified by the data acquired by the AXIe high-speed data acquisition system.The results show that for 1V 40 MHz sine wave signal data,the traditional cumulative average method and average power method can increase SNDR from49.32 d B to 49.35 d B,and the improved calibration method can increase SNDR to 49.36 d B,which is 0.01 d B higher than the former.A time error calibration method based on aitkin stepwise interpolation filter is proposed,and is combined with LMS iterative algorithm to estimate and calibrate the time error.The time error calibration method based on Aitkin stepwise interpolation filter is verified by simulation.Experimental results show that the signal-to-noise distortion ratio can be increased to more than 64 d B for input signals of different frequencies after the time error is calibrated by this method,and that this method can adjust the order of filter according to the requirement of calibration accuracy automatically.3.Architecture of AXIe and specifications,instrument function groups and architecture of IVI driver are studied.The use of IVI-COM driver is studied.Using the IVI-COM driver,the function that AXIe high-speed data acquisition instrument can be programmatically operated by the upper computer software is realized.4.The upper computer software is designed with MFC framework,Iocomp control,IVI driver and the above mismatching errors calibration method.The functions of data acquisition,mismatching errors calibration and data waveform display are realized in this software.The function of upper computer software is verified on AXIe high-speed data acquisition system composed of M9505 A,M9703A and M9536 A.The experimental results show that the upper computer software can programmatically operate the acquisition system,obtain the data acquired by the system,effectively calibrate the mismatching errors of the acquired data,and display the waveform of the data normally.Experimental results show that the upper computer software can programmatically operate AXIe high-speed data acquisition instrument M9703 A,obtain the data acquired by the instrument,calibrate the mismatching errors of the acquired data effectively and display the data waveform normally. |
