We introduce and analyze a method for stabilizing test parameters and estim
ating the non-linearity of mildly non-linear quantizers by Fourier analysis
of the quantizer's output to sinusoidal input signals. Stabilization for t
he combined effects of the rounding operation of the quantizer and the vari
ations in offset and amplitude of the applied sinusoid is achieved by a det
erministic form of subtractive dithering, called wobbling. It thus appears
that one can retrieve low-to-medium degree non-linearities whose contributi
on to the quantizer's distortion in the relevant frequency range is of the
same order as or well below the distortion due to rounding before wobbling.
For the analysis of the method a thorough investigation of the spectra of
sampled, quantized sinusoids (wobbled or not) has to be made. As such we co
mplete and extend existing results in the literature of spectra of this typ
e. The method is potentially useful for estimating the integral non-lineari
ty of AD-converters. (C) 2000 Elsevier Science B.V. All rights reserved.