在等效鉴相频率的基础上,提出了一种新型氢原子频标锁相系统的设计方案.利用频率信号间相位差变化的规律性,无需频率归一化便可完成相互间的线性相位比对即异频鉴相.将异频鉴相应用于主动型氢原子频标的锁相环路中,通过参考信号和被锁信号间等效鉴相频率的合理选择,可以做到异频率信号间的直接鉴相并能获得很高的锁相精度.实验结果表明了该设计方案的科学性和先进性,其锁相精度可达10-12/s量级,与传统氢原子频标锁相系统相比具有电路简单,锁相精度高,附加噪声小,可以异频直接锁相等特点,因而在导航定位、空间技术、通讯、计量、精密时频测控等领域获得广泛应用.
A novel design scheme of phase-locked system of hydrogen maser frequency standard is proposed based on equivalent phase comparison frequency.Using the regularity of the variation of phase difference between frequency signals,linear phase comparison is possible without the same frequency between them,namely different frequency phase comparison.If different frequency phase comparison is used in PLL of the hydrogen maser frequency standard,through suitable choice of the equivalent phase comparison between reference signal and locked signal,we can directly compared phase between different frequency signals and obtain very high phase-locked precision.Experimental results show that the design scheme is advanced and scientific.Its phase-locked precision can reach the order of magnitude of 10^-12/s.Compared to traditional phase-locked system of hydrogen maser frequency standard,the system is high in phase-locked precision,simple in circuit structure,small in additional noise,and can be direct phase comparison between different frequency signals.Thus it is widely used in navigation positioning,space technology,communication,metrology,precise time-frequency measurement and control and so on.