The Research On Crystal Oscillator Of Low Phase Noise And High Stability

With the wide use and quick development of modern electronic systems, higher requirements have been put forward to high precision frequency sources used in standard signals. Phase noise measurement now plays an increasingly important role in the research and performance measurement of the basic frequency sources.This paper studied on the crystal oscillator phase noise, in the second chapter it begins with the phase noise as the frequency stability indicator in frequency-domain, and the’Allan variance’indicator in the time-domain, and gives a practical way to transform the phase noise in frequency-domain into’Allan varianpe’, which is used for analyzing the measurement results in the end. In the third chapter, some common methods of reducing the crystal oscillator phase noise is introduced, such as the design method of oscillating circuit, the optimization of low-frequency loading and feedback, filter technique and the impedance matching of the noise, which are used in the real circuit design of crystal oscillator. At the end of this paper, the final oscillator circuit design drawing is given, the way to choose circuit parameters is analyzed and the debugging procedure and results are given.