Oven controlled crystal oscillator

Abstract

An oven controlled crystal oscillator (OCXO) is provided for improving temperature characteristics of a frequency. In the OCXO, a thermostatic oven 5 (20a) is provided in a thermostatic oven 9 (20b), a temperature control circuit 13 controls a temperature in the thermostatic oven 9 based on a temperature detected by a temperature sensing element 10, a first resonator 1 and a second resonator 2 are provided in the thermostatic oven 5, a temperature control circuit 8 controls the temperature based on an oscillation frequency difference between the two resonators, and especially, the temperature control circuit 13 controls the temperature to be within the temperature region where the oscillation frequency difference between the first resonator 1 and the second resonator 2 corresponds with the resonator temperature in a one-to-one manner, and the temperature gradient is either in a positive direction or in a negative direction.

Description

[0001] cross reference [0002] The present invention is based on and claims the priority of Japanese Patent Application No. 2013-172975 filed on August 23, 2013, the entire content of which is incorporated herein by reference. Technical field [0003] The invention relates to a crystal oscillator with a constant temperature bath, in particular to a crystal oscillator with a constant temperature bath which can improve the temperature characteristic with respect to frequency. Background technique [0004] [Existing Technology] [0005] The existing Oven Controlled Crystal Oscillator (OCXO) with a constant temperature bath includes a temperature bath that keeps the temperature at a fixed temperature, and the crystal oscillator is housed in the constant temperature bath to perform stable oscillation that is not easily affected by external temperature . [0006] Moreover, in the existing OCXO, some oscillate two vibrators with different frequencies and different temperature gradients, and...

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Problems solved by technology

[0038] However, in the conventional OCXO, there is a problem that the combination of vibrators whose oscillation frequency difference changes linearly with temperature is limited to the temperature at which the temperature gradient of the vibrator frequency becomes minimum (zero temperature coefficient (ZTC) Temperature) is different AT cut crystal resonators, when using AT cut resonators, the rate of frequency change relative to ambient temperature (ambient temperature) is small, that is, SC cut / IT cut with high frequency stability relative to ambient temperature, etc. During secondary rotary cutting, the change of frequency difference due to temperature is not linear, so temperature control cannot be performed

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