Channel mismatch estimation method for broadband cross sampling system

Abstract

The invention belongs to the technical field of broadband signal sampling, and relates to a channel mismatch estimation method for a broadband cross sampling system. Offset mismatch estimation is carried out on noise data acquired by the broadband cross sampling system. An amplitude value and a phase value of each channel are acquired at each test frequency point by adopting a sine fitting estimation method. A reference channel is selected to obtain a gain discrete function and a phase difference discrete function of each channel at each test frequency point. Frequency range expansion is performed on the obtained gain discrete function and phase difference discrete function of each test frequency point to obtain a gain mismatch frequency response and a phase mismatch frequency response ofeach channel. By removing the influence of bias mismatch, estimation precision of channel mismatch is improved. Only data acquisition and processing need to be carried out on a frequency band of interest, gain mismatch and phase mismatch of a frequency band of no interest are obtained by carrying out frequency range expansion on a gain discrete function and a phase difference discrete function ofeach test frequency point, and the workload of data acquisition and processing in the channel mismatch estimation process is reduced.

Description

technical field [0001] The invention belongs to the technical field of wideband signal sampling, and relates to a channel mismatch estimation method for a wideband cross-sampling system. Background technique [0002] High-speed and high-resolution sampling systems are key components of wideband digital receivers, communication systems, oscilloscopes and other instruments. The contradiction between high sampling rate and high resolution restricts the development of analog-to-digital converter (ADC, Analog-to-Digital Converter). Cross-sampling (TIADC, Time-Interleaved Analog-to-Digital Converter) technology can effectively solve this problem. The ideal structure of the M-channel cross-sampling system is as follows: figure 1 shown. Multiple ADCs with lower sampling rates alternately acquire signals at the same clock frequency and different clock phases, and then combine the sampling sequences of the sub-ADCs as the system output to increase the sampling rate. [0003] While...

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Problems solved by technology

Crossover is given in reference (J.Li, J.Pan and Y.Zhang, "Automatic Calibration Method of Channel Mismatches for Wideband TI-ADC System", Electronics, 2019, 8(56), pp.1-13.) Estimation method of gain mismatch and phase mismatch in the sampling system, but does not describe the estimation method of bias mismatch, and the influence of bias mismatch is not removed before the data is estimated for gain mismatch and phase mismatch, which reduces the channel The estimation accuracy of the mismatch; the frequency of the test frequency point in this article needs to cover the entire first Nyquist domain, which increases the workload of data acquisition and processing

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