Theoretical and experimental investigations of 1/f noise in quartz crystal resonators

Fluctuation dissipation theorem allows to recover a 1/f noise spectral density at low frequency. The level of this 1/f noise is governed by a single fitting parameter that can be connected to the onset frequency of this 1/f regime. It constitutes the fundamental intrinsic limit of quartz crystal. Some preliminary considerations on the physical origin of this parameter in terms of microscopic processes in the crystal are given. Experimentally, quartz crystal resonators have been cut from a quartz crystal block supplied specifically for this study on 1/f noise. The short-term stabilities of several resonators have been measured to be lower than 8-10^-1. A comparison of these resonators is given and the results are discussed according to the position of the resonators inside the crystal block.