The quartz crystal in an electronic oscillator needs to be maintained at a constant operating temperature to prevent changes in its frequency due to variations in the ambient temperature.
Therefore, in order to maintain the crystal oscillator at a required temperature, it is housed in an oven with the thermostat devise that indicates the existence of the calibrated oven temperature. Such an improvised devise is called OCXO-Oven controlled crystal oscillator.
Normal operating temperature of a standard commercial OCXO is 75 °C but would vary from 30 – 80 °C depending upon the set-up and that of its industrial version is specified to -40 – +85 °C
Thus, such a design of an OCXO prevents temperature drifts and provides the highest stability that a crystal oscillator can provide. Further, frequency stability is also fine-tuned by the types of cuts on the quartz crystal-AT Cut and SC Cut.
Therefore it is quite obvious that OCXO is predominantly used in applications where the frequency control is a crucial factor like radio transmitters, cellular base stations, defense communication devices, and precision frequency measurement equipment.
OCXO is bulkier in size, expensive and power-consuming. However, the frequency and temperature stability provided by OCXOs are much better than what the TXCOs provide.
Routine service checks are recommended to assess the health of performing elements.