Oven Controlled Crystal Oscillator Basics
Pre-heat to 185ºF
Setting OCXO Oven Temperature
Better Ingredients, Better Pizza Oscillators
AT vs. SC cut crystals
- Improved Frequency Stability: You can see from the graph above the response of the SC cut is much flatter over a wider temperature range than the AT cut. This translates to tighter frequency stability over temperature.
- Higher Operating Temperature: The turning point of SC cut crystals is higher than AT cut crystals which make them ideal for ovenized applications. The drawback of this higher turning point is the sharp roll-off at lower temperatures. Because of this trait, the SC cut crystals are only suitable for ovenized oscillators and will not work well in other oscillator configurations (TCXOs, VCXOs, etc.)
- Improved Aging: SC cut crystals (which stands for “stress compensated”) offer improved aging performance that is 2 to 3 times better than AT cut crystals.
- Warm-up time: An SC cut OCXO will settle in at it’s final frequency much faster than a comparable AT cut OCXO.
- Phase Noise: The SC cut crystal offers much better Q (quality) factors than AT cut crystals. As such, the close-in or close to the carrier phase noise of the OCXO is improved.
- G-sensitivity: The stress compensation of the SC cut crystal also reduces the g-sensitivity of the oscillator. Quartz is a electro-mechanical devices… if you apply a voltage across the crystal, it will oscillate. The downside is that if you apply a vibration across the crystal it will induce a voltage. This voltage shows up as acceleration or vibration induced phase noise.
One of the Greatest OCXO Challenges...Solved!
One of the biggest challenges with OCXOs is maintaining excellent frequency stability. Bliley's high-quality, ultra-stable OCXOs offer excellent frequency stability in even the toughest environments.
See how Bliley's 85+ years of frequency control experience can take your ultra-stable needs further!