A new method for determination of the frequency spectrum of a quartz crystal and its applications

Abstract
A new experimental method is presented for determination of the frequency spectrum of a quartz crystal. The method consists of coupling a tunable parallel LC network across the quartz crystal in a crystal oscillator circuit. As the LC resonant frequency is brought in the proximity of the frequency of any of the quartz crystal resonant modes, the quartz crystal takes control to generatet his resonant mode. At this stage the frequency generated becomes stable and insensitive to a slight variation in the LC parameters. Thus, by the technique used, the quartz crystal can be excited iints various vibrational modes, the resonance frequencies of which get measured directly. The method described of detecting the various resonant frequencies of the quartz crystal makes it directly possible to obtain a numbeorf stable frequencies from a single quartz crystal. Some applications of the method for properd esign of the crystal shapes and electrode arrangement for specific frequency requirements are also described.