Autocorrelation function of the quantisation-error process for a sinusoid

This letter investigates the variation in the correlation function of a quantisation-error process with the width of quantisation for a sinusoidal-input process. This process does not comply with the quantisation theorem of Widrow, and, in consequence, the orthogonal expansion procedure of Barrett and Lampard is the adopted analysis technique. The results clearly establish that, for this input, the quantisation-error spectrum is white for practical purposes, even when the quantisation is very coarse.