Thermal transient studies of anharmonic sensors of aging of precision AT-cut crystal resonator

The report addresses the thermal transient of the sensor of aging (anharmonic mode h/sub 513/ of AT-cut crystal resonator) of the crystal standard based on the modulational method. The thermal dynamic properties of the aging sensor influence the effect of the aging compensation for the standard. We present the thermal model of a crystal resonator and consider in detail the model of the thermally induced frequency transient in a resonator within the ovenized oscillator. The model has been examined for the aging sensor excited by modulation within the Colpitts oscillator. Based on the model, we digitally simulate the anticipated behavior of the thermally induced frequency of the aging sensor and compare it with that obtained by measurement. Finally, we show how to compensate the temperature dependence of the aging code of the standard.