Temperature sensing and control to improve warm-up time of OCXOs

Warm-up time, which is for the OCXOs to get the nominal frequency stability, is a critical factor for the application of OCXOs. In most OCXOs, the temperature sensing and control method is passive involving heating resistors or power transistors. This kind of configuration makes the normal warm-up time around/above 3 minutes, which is not suitable for the applications requiring quick start and test scenarios. In order to improve the warm-up time, this paper presents a new active temperature sensing and control method by employing a thermoelectric cooler (TEC) to shorten the warm-up time. Test results show the warm-up time could be less than 1 minute and the temperature stability of the OCXO with the TEC is better than the one without the TEC.