Application of the Variable Projection Method to A/D Converter Testing in Dual-Tone Mode
Résumé
This paper deals with time-domain testing of A/D converters in dual-tone mode. The variable projection method reduces this problem to a 2- dimensional nonlinear least-squares (NLS) estimation of the two test frequencies, followed by solving a linear system for estimating the model linear parameters. Various algorithms for solving the NLS problem are examined and compared. The required frequency starting values are generated by an interpolated fast Fourier transform based method which guarantees the global convergence of the algorithms. The algorithm performances are examined through simulations and experimental results and compared with the spectral analysis.