Temperature Compensated Crystal Oscillator Based On Stress

The TCXO is widely used in the communications, the instrumentation, the satellite navigation, and the other fields. It is the essential component in the electronic field. In recent years, the man at home and abroad has increased the research on the temperature compensated crystal oscillator. In this paper, the temperature-compensated crystal oscillator based on stress is different from the traditional TCXO.First, the paper introduces the two characteristics of the crystal oscillator, namely the temperature-frequency characteristics and the stress-frequency characteristics, and analyzes the influencing factors on the characteristics. The different the cut type,the different the frequency characteristics are. So we should distinguish the different cut type crystal first. After determining the cut type, we can get the temperature-frequency characteristics of the crystal and the corresponding stress-frequency characteristics by looking up a large number of experimental data. Determine the direction of the applied stress, and gradually change size of the stress. In the process of gradually change the size of the stress, we can measure the corresponding frequency offset amount and record them. According to the curve of the temperature-frequency characteristics, we can find the corresponding amount of frequency compensation. After that, according to the principle of that the compensation amount should be equal to the frequency offset amount, we can determine the required size of the stress and apply the stress. So the frequency output can be kept stable. Based on this principle, this paper comes up with the temperature compensated crystal oscillator based on the stress by combing the temperature-frequency characteristics and stress-frequency characteristics.This TCXO mainly has three innovations. First, the paper selects the overtone crystal.The traditional TCXO usually uses fundamental crystal, because the fundamental frequency of the crystal pulls better. Second, the paper focuses on the design of the compensation process. With the use of successive coating, temperature-frequency characteristics will also change. We can get the optimum coating thickness. Third, the paper discusses the impact of stress release effect on the crystal. The crystal needs to use stress, so we should take measures to make the stress release effect smaller.The designation and experiments in this paper are at the exploratory stage. Although initially we had some success, making this approach apply to industrial production in the future still need a lot of research and the help of businesses. We believe the idea that using the stress to compensate crystal oscillator is correct. The way to apply the stress by coating and change the stress by successive coating can be achieved. If increasing investment in research in this area, with the continuous efforts, the quality of the production of the crystal will be on the higher level. The TCXO will be with the lower cost, the higher frequency stability. This kind of TCXO will have a good market and it will bring more economic benefits for the Chinese electronics industry.