Spurious signals induced by vibration of crystal filters

The degradation in frequency stability of a sinusoidal signal resulting from transmission through a crystal filter is discussed in detail. An effective acceleration sensitivity vector for the filter is defined, and the degradation in frequency stability in both the time and frequency domains is expressed as a function of this sensitivity. The phase shift through the filter is quantified in terms of the acceleration sensitivity and the filter group delay. By considering typical values of acceleration sensitivity for bulk-wave resonators, it is shown that spurious signals induced by crystal filters can be greater than those induced by crystal oscillators in vibration. The degradation in Allen variance is also considered.<
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