The Newton's Method Applied to ADC Effective Number of Bits Measurement : Tolerated Frequency Uncertainty and Methods for Initial Guess
Résumé
This paper examines in some detail the convergence of the Newton method for dynamic A/D converter testing using sinewaves. A criterion for choosing the initial guess method such that the Newton method converges to the global minimum is determined. It is shown that this criterion is significantly enhanced by a line-search strategy and it can be satisfied easily by a simple method based on interpolated FFT and windowing. In the case where the initial frequency ratio is estimated from the frequencies given by the sinewave and clock generators, a modified sufficient condition is derived from the previous criterion.