High Stability And Low Phase Noise Crystal Oscillator Design And Cad

Whatever it is radar, ECCM equipment, communication equipment or instrument, frequency source with high stability is needed to guarantee the quality of carrier signal. The fundamental unit of the high-reliability frequency source is low phase noise reference source, and the sources with optimum frequency stability of reference sources are high reliable crystal oscillator and atomic clock. Even the atomic clock itself needs high reliable crystal oscillator. Therefore it is important to research the mechanism and noise property of high reliable crystal oscillator. Until now, many experts domestic or abroad have researched it deeply and some results have been obtained. Purchasing one low phase noise crystal oscillator from foreign countries, the price will be thousands (even ten thousands) of yuans. Although the price of local low phase noise crystal oscillator is lower, it is still expensive, and the high reliable crystal oscillator with higher specifications can not be produced domestically yet. The research and development of low phase noise crystal oscillator will not only be with good social benefits, but also be with noteworthy economic benefits.In this paper, the operation principle of the oscillator is analyzed first, from the point of view of theory the designs of crystal resonator and its equivalent circuit, crystal oscillator and thermostatic chamber are defined. The noise model of circuit is used to analyze key factors influencing phase noise of the crystal oscillator, in order to control phase noise of the crystal noise from the very beginning of the design. With CAD technology the high reliable constant temperature crystal oscillator is emulated, then its phase noise property is optimized, which is an guide to the CAD of the low phase noise crystal oscillator hi the future. Secondly a lot of experiments are performed with the developed crystal oscillation circuit, then serious and careful analysis are accomplished for the experiment results, it is proved sufficiently that the design is correct, and the developed high reliable crystal oscillator is up to the advanced level of China. Finally the design method of low phase noise crystal oscillator is given.