Some experiment results of TCXO based on stress processing

We combine the different characteristics of quartz crystal including frequency - temperature characteristics and frequency - stress characteristics, with the influence of stress on the frequency of crystal blank to compensate the temperature influence on the frequency of crystal. A lot of experiments have been done to prove that with stress processing the frequency - temperature performance of overtone crystals can be improved obviously. With this way, the new crystal oscillators can show a good frequency - temperature performance, lower power consumption, lower phase noise and better short-term stability. Now the frequency - temperature stability of the oscillator samples can be better than plusmn 1.5 ppm from -40 to +80 deg. C. To generate the suitable stress, we plate a metal film on the crystal blank to form a temperature - stress sensor based on the different characteristics of quartz and the metal. When temperature changes, there is a possibility for the shape of sensor to be changed also. Therefore, it can apply the stress to the blank of the crystal. We choose overtone crystal and it can show better stability and aging than those of fundamental crystal, and higher frequency - stress sensitivity. The experiments also show that the different metal film shape and position on the blank will generate the different results.