OCXO – The Frequency Sustainer

OCXO stands for Oven controlled crystal (Xtal) oscillator. These are used in devices or  pparatus where a high degree of frequency stability is required.

An oven-controlled crystal oscillator or OCXO is a device that has higher frequency stability.

It is an oscillator, where a crystal oven is used to maintain the quartz crystal, in an oscillator, at calibrated constant temperature. Controlled temperature of quartz crystal helps prevent changes in the frequency that arise due to changes in the ambient temperature.

In spite of quartz having a very low thermal expansion, temperature change remains the prime cause of the minor frequency variation in an OCXO.

It is pertinent to note that the drift in the crystal frequency can also be further controlled by giving the crystal an appropriate “Cut”, in other words, trim it to size and shape-to attain its optimum vibrating stability. An SC cut is the best.

OCXOs are expensive and larger as compared to other crystal oscillators and use power to heat the oven therefore not used in battery-operated circuits. However, the frequency stability offered by OCXO is substantially superior to the conventional oscillators.

Such exceptional frequency stability is required for radio transmitters, cell towers, military communication equipment, and precision frequency measuring equipment.

OCXOs are available in different types of packages and different package styles, and prices. Further, its performance may vary basis the type of OCXO needed to be used.

It is recommended to carry out recalibrations and checks-on crystal and heat element aging to ensure that the device performs at its best at all times.

Raditek offers a whole range of these on its website with stability to 0.1ppm