Crystal oven

This type of oscillator achieves the highest frequency stability possible with a crystal.

Quartz crystals are widely used in electronic oscillators to precisely control the frequency produced.

The frequency at which a quartz crystal resonator vibrates depends on its physical dimensions.

Although quartz has a very low coefficient of thermal expansion, temperature changes are still the major cause of frequency variation in crystal oscillators.

The oven is a thermally insulated enclosure containing the crystal and one or more electrical heating elements.

For this application, the crystal and the thermistor need to be in very close contact and both must have as low a heat capacity as possible.

An OCXO inside an HP digital frequency counter
Miniature crystal oven used to stabilize the frequency of a vacuum-tube mobile radio transmitter
PCB -mounted OCXO from 2016
Some of the earliest crystal ovens. These precision 100 kHz oven-controlled crystal oscillators at the US Bureau of Standards (now NIST ) served as the frequency standard for the United States in 1929.