High-Stability OCXO & OCVCXO Frequency References
Connor-Winfield oven-controlled oscillators are designed for applications requiring tighter frequency control over temperature, aging, and operating conditions, with configurations available for demanding phase-noise and long-term stability requirements.
Why Use an OCXO?
An oven-controlled crystal oscillator maintains the crystal near a controlled operating temperature, reducing the effect of ambient temperature variation on frequency. OCXOs are appropriate when system requirements extend beyond what a compact TCXO can reasonably provide.
Temperature Stability
Maintain tighter frequency control as ambient temperature changes.
Short-Term Stability
Maintains local frequency stability over short averaging periods. Especially important in low-bandwidth PLL and GNSS-disciplined timing systems where the OCXO determines short-term performance between slow external-reference corrections.
Phase Noise
Selected OCXO designs provide strong close-in spectral performance for RF, instrumentation, timing, low-jitter reference, and frequency-synthesis applications.
Aging & Long-Term Drift
Support systems where frequency error must remain controlled over extended operating periods.
Select the OCXO Architecture
Fixed-frequency OCXO or voltage-controlled OCVCXO
OCXO
- Fixed-frequency precision reference
- Tight temperature stability
- Strong aging and long-term frequency control
- Available configurations optimized for low phase noise
- Appropriate where external frequency steering is not required
OCVCXO
- OCXO performance with voltage-control capability
- Allows fine frequency adjustment or disciplining
- Useful in PLL, synchronization, and holdover architectures
- Selection should consider control range as well as stability and phase noise
The correct choice depends on frequency stability, aging, phase noise, warm-up, power, package, control range, and environmental requirements.
OCXO Performance in Timing & RF Systems
OCXO performance specifications matter because they determine how the oscillator behaves inside the actual system. Two common examples are precision GNSS timing systems and low-noise frequency synthesis, where different OCXO characteristics become critical.
GNSS Timing, Synchronization & Holdover
When GNSS is available, the external reference supplies long-term accuracy. In a low-bandwidth disciplined loop, the OCXO provides the stable local reference between corrections. Short-term stability maintains local timing and frequency performance between GNSS corrections.
If GNSS is lost, the system enters holdover. During holdover, temperature stability and aging increasingly determine frequency and timing accuracy until the external reference is restored.
GNSS Available
Short-Term Stability
Low-Bandwidth Discipline
Stable Local Reference
GNSS Lost
Temperature Stability + Aging
System Objective
Accurate Holdover
Low-Noise Frequency Synthesis
When a reference frequency is multiplied by N, its phase-noise contribution ideally increases by 20 log10(N) dB, before the additional noise contributions of the PLL, divider, VCO, and associated circuitry are considered.
Low-Phase-Noise OCXO → PLL / Synthesizer → Frequency Multiplication → Microwave / GHz Output
100 MHz → ×10 → 1 GHz | ideal multiplication contribution: +20 dB
