Characterizing the Noise of Zener-diode Voltage Standards

摘要

We measured the differences between the voltage outputs of pairs of Zener-diode based electronic voltage standards (Zeners) and between Zeners and a Josephson array voltage standard (JAVS). The data are analysed as time series. They are serially correlated so that it is not justified to characterize the dispersion by using the usual expression for the standard deviation of the mean, the experimental standard deviation divided by the square root of the number of measurements. Zener noise is of a 1/f nature and to characterize it we use the Allan variance, a statistic used for such purposes in time and frequency metrology. The uncertainty in the voltage measurements of a Zener is limited by 1/f noise to between 3 and 10 parts in 10~(9) of the nominal output value. We propose methods for estimating the Allan variance of a Zener using either a JAVS or a small group of similar Zeners.