Vibration Conditions, Crystal Oscillator Phase Noise Analysis And Vibration Design

Referenced sources are the key components of the modernization communication and radar equipments. Their performance would directly affect the characteristic of the equipments, especially the sensitivity and selectivity of the receivers.Before the appearance of crystal oscillators, radar system usually use magnetis-controlling oscillators as referenced sources. Because magnetis-controlling oscillators need high voltage and many kinds of power supply, at the same time, their frequency stability is only 10-5,so they can't satisfy the practical requirement. In the 1950's crystal oscillators appearred, and with the development its frequency stability is above 10-10.After then crystal oscillators with the higher frequency stability were widely applied in the telecommunication and radar system.With the development of the radar system and microwave communication technology, the system requirements are becoming higher and high we. As a result of this, referencing sources should have more purer frequency spectrum. So the research on the signal sources with the lower phase noise, higher frequency stability and higher reliability is becoming more and more important. At the same time many scientists and experts pay more energy on the research on the testing system and technology.In the practical work the crystal oscillators would be affected by kinds of environment conditions.In the application of space technology,how to reduce the impact of the acceleration on crystal oscillators,becomes more and more important.In the 1950's report scientists began the research on how acceleration influences crystal oscillators.The research mostly focused on two sides. On the one hand the research focus on the reliability of the crystal oscillators under the acceleration.On the other hand the research is focus on the imfact of the crystal oscillators on the acceleration.Firstly, the paper researches and concludes the primary factors on how phase noise come into being and the acceleration influence phase noise. In the design of the crystal oscillators, the phase noise is the focus of the design.The crystal oscillators with lower phase noise have the purer frequency spectrum,and the strong anti-jamming ability. Secondly through lots of vibration experiments the paper analyses the results and conclude the mechanism. Thirdly the paper design the vibration-isolator and optimize it.The paper focuses the design of the crystal oscillators and its vibration-isolator.Its output power is 8dBm.Its frequency stabilization is±5PPM.Its harmonics is≤-30dBc. Its non-harmonics is≤-80dBc.Its phase noise is as follows: L (10Hz)≤-90dBc/Hz, L(100Hz)≤-110dBc/Hz, L (1kHz)≤-150dBc/Hz, L(10kHz)≤-160dBc/Hz,L(100kHz)≤-160dBc/Hz.Without the vibration-isolator, crystal oscillator'phase noise is about 40dB under the C level vibration in the range of 10Hz to 10kHz. With the vibration-isolator, the influence is improved. In the range of 10Hz to 10kHz, deterioration is lower than 15dB and in the range of 10k to 100kHz, deterioration is lower than 10dB。In the end the paper concludes the research, and points out the content and object of the next work .