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Thickness Shear Mode Resonators References, from Sandia National Labs Tutorial on Quartz Crystal Resonators and Oscillators (2001), by John R. Vig The Aging of Bulk Acoustic Wave Resonators, Filters and Oscillators (1991), by John R. Vig & Thrygve R. Meeker The aging of quartz crystal resonators, filters and oscillators is reviewed, including the topics of: the impacts of aging, typical aging characteristics, aging specifications, aging mechanisms, temperature dependence of aging, frequency and overtone dependence of aging, drive level dependence of aging, the effects of aging interruptions, the dependence of aging on material and mode type, the state-of-the-art in low-aging oscillators, and aging acceleration effects. The aging mechanisms discussed include: contamination transfer effects, stress effects, electrode effects, diffusion effects, changes in the quartz material, and circuit and other electrical changes. Isothermal and thermal step stress aging acceleration methods are also reviewed. Influence of a Magnetic Field on Quartz Crystal Resonators (1996), by Remi Brendel The magnetic sensitivity of quartz crystal resonators is a consequence of the ferromagnetic properties of the metal used as support for the vibrating plate. Various magneto-mechanic interactions can contribute to the overall sensitivity, the most important of which is shown to be the change in Young's modulus of the spring material submitted to a magnetic field, which in turn modifies the stress in the quartz plate and then induces a change in the crystal resonant frequency. The experimental setup and procedure are described and a large number of experimental results obtained with resonators of different technologies are presented and discussed. A comparison between the magnetic behavior of identical resonators mounted with different materials definitely proves the responsibility of the supports in the magnetic sensitivity of resonators and gives interesting information on its reduction. Thermodynamic Aspect of Short Term Frequency Stability of Directly Heated Resonators (2002), by Igor Abramzon & Roman Boroditsky This paper is an attempt to study a problem of degradation of short-term stability (STS) of OCXOs based on the directly heated resonators (DHR) due to variations in the heating power. The analytical model linking the DHR frequency fluctuations with the heating current and ambient temperature variations, as well as the DHR properties has been obtained and verified experimentally. The carried out research allowed development of the means for designing DHR with STS better than 5E-12 per 1 s, which is comparable to the best results attainable with the conventional technique of heating the crystal. Low Phase Jitter in UHF Band VCXO (2003), by D.V. Bogomolov, R. Boroditsky & E.A. Silaev Considerations when Specifying Crystal Oscillators to Optimize System Jitter and Phase Noise (2008), by Dan Nehring Many parameters will need to be specified for a purchased oscillator and one will need to optimize the system to best preserve and utilize the signal. This paper will focus on a few practical considerations pertinent to end result jitter and noise performance, assuming a low noise crystal reference which may be multiplied to microwave frequencies is being designed in. |