2111 Comprehensive Drive
Aurora, Illinois 60505
Phone: 630-851-4722
Fax: 630- 851- 5040
www.conwin.com
Specifications subject to change without notice. All dimensions in inches. © Copyright 2012 The Connor-Winfield Corporation
Application Note
AN2093
Page
5
Revision
P01
Date
10 May 2013
3.1 OCXO Theory of operation.
The OCXO encloses a crystal in a temperature-controlled chamber called an oven. Frequency stability is achieved
by maintaining tight temperature control of the crystal within the oscillator oven. Care must be taken not wick thermal
energy away from the OCXO preventing the core from reaching thermal equilibrium.
When an OCXO is turned on, it goes through a ‘‘warm-up’’ period while the temperature of the crystal in the internal
oven stabilizes at a temperature significantly warmer than ambient.
During “warm-up”, the performance of the oscillator will not meet the specified frequency stability until normal
operating temperature is reached. After the oven has “bridged” the temperature within the oven remains constant as
ambient varies.
The oven controller operates such that if the internal temperature of the oven decreases due to an ambient
temperature drop, the oven controller will provide more power to compensate for thermal losses. Similarly, an increase
in ambient temperature causes a reduction in applied power into the oven and the compensation temperature
decreases.
In most modern designs additional heat is considered a problem and will cause most devices to degrade in
performance or eventually fail. The heat generated within the OCXO oven core is used to maintain a constant
temperature at the crystal.
“During “warm-up”, the performance of the oscillator is degraded until normal operating temperature is reached.”
Section 3: Theory of Operation / Characterization.
Figure: 5-01
For further information please contact Connor-Winfield Engineering Department.
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