Amplitude-frequency effect of Y-cut langanite and langatate

Amplitude-frequency effect of a Y-cut langanite (LGN) resonator and a Y-cut langatate (LGT) resonator were measured. The frequency shifts from the baseline frequency with 1 mA were measured as a function of drive currents up to 28 mA. High-drive current shifted the frequency, but it also heated the crystal locally, causing temperature-related frequency changes. The local heat transfer and its influence on the frequency were analyzed. The amplitude-frequency shift was effectively measured, and was not affected by the temperature-related frequency changes. The 3rd, 5th, and 7th overtones (OT´s) were found to behave as soft springs, i.e., resonant frequency decreases as drive current increases. The drive sensitivity coefficients of the 3rd and 5th OT´s are in the vicinity of -2 ppb/mA/sup 2/ for both resonators. The 7th OT´s are higher than the other OT´s: -5/spl sim/- 7 ppb/mA/sup 2/. The lowest drive sensitivity is -1.2 ppb/mA/sup 2/ on the 5th OT of the LGT.