Single ADC acquisition channel dynamic characteristic test method

Abstract

A single ADC acquisition channel dynamic characteristic test method belongs to the field of electronic measurement. The test flow comprises steps of sampling the excitation signals to obtain an observation sample; determining the frequency search boundary and the frequency selection point, calculating the least squares residual corresponding to the frequency selection point, and determining the model of the base frequency signal; estimating the signal to noise ratio SINAD and the effective number of bits ENOB; constructing the residual sequence matrix, calculating the covariance matrix, performing the feature decomposition, searching and calculating the harmonic frequency in the neighborhood of the corresponding peak, and estimating the harmonic amplitude; and estimating the signal non-harmonic ratio SNHR, the spurious-free dynamic range SFDR and total harmonic distortion THD. The method firstly adopts a method of combining time-frequency domain analysis and spatial spectrum analysis, can accurately estimate the excitation signal, the noise component and the harmonic distortion component contained in the observation sample, and can effectively improve the spectrum leakage and fence effect in the spectrum analysis. The estimation is highly precise, the calculating amount is small, and the hardware implementation is easy.

Description

technical field [0001] The invention belongs to the field of electronic measurement, in particular to a method for testing the dynamic characteristics of a single ADC acquisition channel. Background technique [0002] During the dynamic working process of the acquisition circuit, due to the uncertainty of the sampling clock, the error generated by the nonlinear components in the acquisition circuit, the quantization error of the analog-to-digital conversion, and the harmonic distortion and other factors, the circuit is in the process of analog-to-digital conversion. Various errors may occur. The test and evaluation of the dynamic parameters of the acquisition channel is a quantitative characterization of these error terms. There are two main types of testing algorithms for the dynamic characteristics of acquisition channels using sine wave signals: one is non-parametric methods, the typical algorithm is discrete Fourier transform (Discrete Fourier Transform, DFT) and its fa...

AI Technical Summary

Problems solved by technology

Compared with the traditional four-parameter sinusoidal fitting algorithm, this algorithm eliminates the need to strictly select the initial frequency, but it needs to be repeatedly screened, and the calculation and complexity of the algorithm are high.

[0004] The disadvantage of the existing technology is that the actual sampling process is mostly incoherent sampling, and the FFT spectrum analysis is directly performed on the quantized output samples of the sinusoidal signal, which will cause spectrum leakage and fence effect, and the frequency resolution is low

Increasing the sample observation length can improve the spectral resolution to a certain extent, but it cannot solve the fundamental problem, and leads to an increase in algorithm calculation and hardware storage cost

And when the frequency parameters cannot be accurately known, the traditional four-parameter sine fitting algorithm is a nonlinear iterative problem. If the initial frequency parameter is not selected properly and the number of iterations is large, the algorithm may eventually converge locally or even diverge.

In addition, the parameter estimation based on wavelet transform, the estimation accuracy depends on the selection of the mother wave, and the harmonic signal parameters cannot be directly estimated

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