A method and
system for
bandwidth extension of a critical sampling circuit, belonging to the field of
signal sampling technology. The implementation method is as follows: S1, estimating the model coefficients of the squared
amplitude response of the simulated channel of the critical sampling circuit through ultra-relaxed primordial duality, constructing the simulated channel response matrix, and obtaining the
system response matrix by row
decimation; S2, establishing the high-dimensional response matrix of the critical sampling circuit and completing parameter initialization; S3, performing iterative calculation of the extension features through
elastic network regression, checking the convergence of the extension residual or the number of iterations, if satisfied, proceeding to S4, otherwise continuing iteration; S4, reconstructing the high-dimensional
signal using the extension features calculated in S3, and obtaining the reconstructed
signal after
bandwidth extension of the critical sampling circuit through sampling rate conversion. This invention, by iteratively calculating the spectral characteristics within the target extended bandwidth of the critical sampling circuit, can recover out-of-band lost spectral information without increasing the sampling
clock frequency and analog input bandwidth, achieving low-cost high-frequency signal sampling.