Dual-channel TIADC frequency response mismatch real-time calibration method for narrowband signal sampling

Abstract

The present invention provides a dual-channel TIADC (time-interleaved A / D converter) frequency response mismatch real-time calibration method for narrowband signal sampling. According to the method, a frequency response function in a polynomial form is adopted to characterize the linear mismatch characteristic of a system; Gaussian white noises are artificially superimposed to narrowband input signals, so that obtained signals are adopted as the input signals of a TIADC; mismatch information is obtained by using slight oversampling; mismatch error is estimated when being corrected by using a variable step size least mean square error (VSSLMS) algorithm in real time; compared with a basic LMS algorithm, the VSSLMS algorithm has fast convergence performance in a large error range and low mismatch quantity in a small error range, thereby improving tracking performance; corrected output is obtained, a filter is designed to filter out the white noises, so that desired output can be obtained. With the method adopted, the problem that the narrowband input signals cannot avoid the problem of error energy on an oversampling tape can be solved; and it can be ensured that the parameters of the system can converge to be accurate values, so that effective correction can be realized. The method has the advantages of simplicity, easiness in implementation and excellent calibration effect.

Description

technical field [0001] The invention relates to the technical field of signal sampling and processing, and more specifically, to a real-time correction method for dual-channel TIADC frequency response mismatch for narrowband signal sampling. Background technique [0002] With the continuous development of integrated circuit technology and the promotion of digital technology, the requirements for the sampling rate and sampling accuracy of the analog-to-digital conversion device ADC are getting higher and higher. Not only the data acquisition system is required to have a high sampling rate, but also a high sampling rate precision. In actual application, there is a high dependence on the real-time sampling rate and sampling accuracy. However, the maximum sampling rate of ADC is limited by its resolution. There is a contradiction between resolution and sampling rate. High sampling rate requires shorter conversion time, while high resolution requires longer conversion time. Acc...

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Problems solved by technology

[0006] The present invention provides a method for narrowband signal sampling to solve the defect that the correction algorithm fails due to the fact that the narrowband signal cannot ensure that the mismatch error appears on the oversampling band when correcting the sampling result of the narrowband signal in the prior art. A real-time correction method for dual-channel TIADC frequency response mismatch. This correction method artificially superimposes Gaussian white noise on the narrowband signal as the input signal of the 2-TIADCs system, thereby using slight oversampling to obtain the mismatch error signal. The mean square error (VSSLMS) algorithm performs real-time estimation and correction on the mismatch error signal, and after obtaining the corrected output, a filter is designed to filter out Gaussian white noise to obtain the desired output

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