OCXO for Military, Aerospace & Telecom Timing

At the top layer of the timing application pyramid, systems in military, aerospace and telecom master clocks demand the highest possible frequency stability and phase noise performance. As Oven Controlled Crystal Oscillators (OCXO), FCom Fuji Crystal’s OCXO family for military, aerospace & telecom timing applications is designed exactly for this layer, combining SC-cut crystals, precision temperature control and low-noise oscillator architectures.

ppb-level stability Ultra-low phase noise Stratum 3 capable SC-cut crystal SMD & DIP options

Typical applications:

Airborne and shipborne radar timing references
Military and protected communication master clocks
Satellite communication terminals and earth stations
Telecom PRTC/PRC and Stratum 3 holdover clocks
High-end measurement equipment and frequency standards

FCom Fuji Crystal OCXO family for military, aerospace and telecom timing applications

If you are architecting end-to-end references for GNSS, satcom or telecom nodes, learn how to build a complete SAW + TCXO + OCXO timing stack from antenna protection to master-clock holdover.

Key Features of the OCXO Family for Military, Aerospace & Telecom Timing Applications

ppb-level frequency stability over wide temperature ranges with SC-cut crystals.
Ultra-low phase noise suitable for narrowband communication, radar and coherent processing.
Stratum 3–class performance for network synchronization and holdover operation.
SMD and DIP packages from compact 14.7×9.6 mm to rugged 36.3×27.2 mm footprints.
3.3 V / 5.0 V supply options for compatibility with legacy and modern platforms.
Long-term reliability with low aging and robust hermetic construction.

Product Line-Up for Military, Aerospace & Telecom Timing Applications

The table below summarizes typical OCXO series in this family for military, aerospace & telecom timing applications. Detailed datasheets and custom options are available on request.

Series	Package	Crystal Type	Typical Stability	Temp. Range	Highlights
FOC-5S-LN	14.7 × 9.6 × 8.2 mm SMD	SC-cut	±10 ppb	–40 to +85 °C	Ultra-low phase noise, compact SMD form factor, ideal for airborne/vehicle-mounted systems.
FOC-6S	25.4 × 22.1 × 11.0 mm SMD	SC-cut	±10 ppb	0 to +70 °C (typical)	High-stability OCXO for radar, base stations and master clocks where board space is available.
FOC-4D	36.3 × 27.2 mm DIP	SC-cut	ppb-class	Wide temp options	Rugged DIP package for ground radar, earth stations and lab-grade frequency standards.
FOC-1D / FOC-2D / FOC-3D	20.3 × 12.7 mm to 25.4 × 25.4 mm DIP	SC-cut	ppb-class	0 to +70 °C / extended	Family of OCXO references for telecom, digital switches and precision measurement equipment.
FOC-7S	9.7 × 7.5 mm SMD	AT/SC-cut (series dependent)	±20 ppb	–40 to +85 °C	Miniature OCXO for size- and power-constrained L1 edge nodes and portable instruments.

For complete electrical specifications, phase noise plots and aging data, please refer to each product’s dedicated datasheet or contact the FCom Fuji Crystal technical team.

Typical Military, Aerospace & Telecom Timing System Architectures

Master Reference for Radar and Satcom

In radar and satellite communication systems, an OCXO such as FOC-5S-LN or FOC-6S often acts as the core frequency reference:

OCXO provides a clean 10 MHz or 20 MHz reference.
Frequency synthesizers multiply and translate this reference up to microwave LO frequencies.
Downstream SAW filters and digital signal processing rely on this reference to maintain phase coherence.

Telecom Master Clocks and PRTC/PRC

For telecom master clocks, the OCXO is combined with GNSS receivers and network synchronization:

The OCXO delivers short-term stability and low phase noise.
GNSS or network references provide long-term accuracy.
Holdover algorithms rely on the OCXO’s stability when external references are lost.

For deeper phase-noise, holdover and mission-profile context, read our ultra-low-noise OCXO application guide.

FAQ – OCXO Timing Family for Military, Aerospace & Telecom Timing Applications

How do I choose between FOC-5S-LN and a larger OCXO such as FOC-6S or FOC-4D?

If your design is space-constrained (airborne, vehicle-mounted, compact rack modules) and you need ultra-low phase noise with Stratum 3–class stability, FOC-5S-LN is often the best fit. When space and power are less constrained, larger SC-cut OCXO such as FOC-6S or FOC-4D offer additional thermal mass and mechanical robustness for ground stations, radar rooms and lab equipment.

Can these OCXO be used as PRTC/PRC references in telecom?

Yes. This OCXO family is designed to support telecom synchronization, including Stratum 3 performance. In combination with GNSS receivers and SyncE/IEEE 1588 clock ICs, they form the core of PRTC/PRC and grandmaster clock solutions.

Do you support custom frequencies or stability classes?

FCom Fuji Crystal supports custom frequencies, stability options and environmental screening for many OCXO families. Please contact our sales and engineering teams with your target frequency, temperature range, g-sensitivity and reliability requirements.

Ready to design at the top of the pyramid? Our OCXO experts can help you select the right series and options for your radar, satcom, military communication or telecom master clock project.

Learn more about our timing portfolio: Timing Devices Overview · OCXO product overview · What Are Timing Devices?