Advantages and Disadvantages of OCXO SC cut crystal oscillator

This page covers advantages and disadvantages OCXO SC cut crystal oscillator. It mentions OCXO advantages and OCXO disadvantages of SC cut crystal oscillator type compare to other crystal oscillator types.

What is OCXO:
The term OCXO refers to Oven Controlled Crystal Oscillator. It is widely used in communication devices due to its ability to automaticallly keeps temperature of crystal constant and consecutively frequency output inspite of ambient temperature variation.

It provides highly stable frequency output. The figure-1 depicts inside of OCXO crystal oscillator type.
Refer OCXO basics and OCXO types>> for more information.

Advantages of OCXO SC cut crystal oscillator

The figure-2 depicts temperature versus frequency response curve of all the three OCXO types viz. AT cut, IT cut and SC cut. Following are the advantages of OCXO SC cut type:
➨It offers higher frequency stability over wide temperature range compare to other crystal types.
➨It offers high turning point or higher operating temperature.
➨It offers improvement in aging performance which is about 2-3 times better compare to AT cut crystal type.
➨It has lower warm up time compare to AT cut type. Hence it gets settled to final frequency faster.
➨Due to higher Q (Quality factor) performance, it offers better phase noise specification.
➨It offers lesser G-sensitivity due to stress compensation feature.
➨SC crystal is less frequency sensitive against change in physical orientation compare to AT crystal type.
➨SC cut crystal generates lower amplitude spurious output when subjected to vibration.

Disadvantages of OCXO SC cut crystal oscillator

Following are the disadvantages of OCXO SC Cut Crystal Oscillator:
➨Due to high turning point, it has sharper roll-off at low temperatures and hence OCXOs are used only in ovenized type of oscillators and not in other configurations such as TCXOs or VCXOs etc.
➨Manufacturing costs are high due to increased labor costs. This is because of poorer yields of SC cut compare to AT cut type.
➨Delivery or lead time is higher compare to AT cut.

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