Assessment of the uncertainty associated with synchronization error in analog to digital conversion with dither and CAV
Anna Domanska
Abstract:
The paper discusses the problem of cumulative averaging (CAV) of digital signals after the analog to digital conversion with dither signal. The CAV algorithm performs three operations: division of the signal into a set of repetitions, synchronization of sectors of each repetition and cophasal averaging of samples. The influence of non-ideal synchronization of digital sectors on the value of samples of signal being a result of CAV was assessed. A dependence determining the variance of the signal value after averaging was given because of synchronization error. In the case of sinusoidal signal, the variation depends on: synchronization error variance, signal amplitude, relation between signal frequency and sampling frequency, and the number of signals averaged. With non-zero synchronization error, CAV – reducing additive noise – causes distortions in actual values of signal being a result of averaging, and increases the uncertainty value of such a-d conversion result.
Keywords:
a-d conversion, dither, synchonous digital averaging
