Low Noise Frequency Conversion Technology And The Improvement On Rubidium Frequency Standard

With the rapid development of science, the demand on the short-term stability and phase noise performance of frequency standards is also increasing. This paper presents a new type of low noise frequency conversion circuit based on the research of phase noise conception, generation as well as relativity measurement method. On this circuit, utilizing OCXO 8600,which have only one 5-MHz output frequency, we obtain a 100-MHz frequency standard with the same short-term stability and phase noise performance as OCXO 8600.In conventional passive rubidium frequency standards, because in the locking loop there are physics package,frequency transformation circuits and servo amplifier, although the output signal of the standards is very accurate and with a good long-term performance, its short-term stability and phase noise performance are poorer than those of the voltage control crystal oscillator. This paper introduces an approach based on unreal time control, which can improve the short-term stability and phase noise performance of the passive rubidium frequency standards.