OCXO

OCXO (short for Oven Controlled X-tal (Crystal) Oscillator) is a technique used for avoiding temperature changes that affect the resonance frequency of a piezoelectrical crystal.

A small oven is used for heating the crystal to a temperature well above the temperature of its working environment, typically 70–80 degrees Celsius. In many application, this can improve the stability of the crystal by a factor ten or more.