The basic principle of feedback crystal oscillator is analyzed . the basic concept of frequency stability is also introduced , following by the usual expression of phase noise in frequency domain and phase jitter in time domain . further , we describe the origin of crystal oscillator ' s phase noise and phase jitter , also list a variety of its contributors 然后从理论上分析了反馈型晶体振荡器的基本工作原理,并阐述频率稳定度的概念,给出了在频域中相位噪声和时域中相位抖动的表示方法,形成原因以及影响相位抖动的诸多因素。
The concept of viffoal laser frequency stabilizaion is put fowi . the frequency stabilizaion at the center of doppler curve has been realized aller signal detecting , phase sensitive detecting , integrating and high voltage amplifying circuits with fm spectroscopy a frequency stability of l0 - , has been obtained with a reproducibility of l0 - 9 . hyperfine spectra of , ' , i , near 532nm have been studied via modul8tion tfansfer spectroscopy 利用fm光谱法将激光单次通过碘吸收室进行线性吸收，再经信号检测、混频、积分和高压放大等伺服电路，实现了在多普勒曲线中心处的频率稳定，频率稳定度和复现性可达10 ~ ( - 9 )量级。
The technology of frequency synthesis is important in latter - day communication system . it ’ s widely used in wireless communication and electron system . with the high - speed development of technologies , higher stability , higher purity , broader range and larger output number of frequency are required in the frequency source of frequency synthesizer which is the core of this technology 频率合成技术是近代通信系统的重要组成部分,在无线电通信与电子系统的各个领域中得到了广泛的应用。随着各种技术的飞速发展,人们对频率合成器的频率稳定度、频谱纯度、频率范围和输出频率的个数提出了越来越高的要求。
In this circuit , reference current sources are used to charge and discharge capacitors . this oscillator ’ s output is very ideal through control circuit under 5 . 7v reference voltage , and oscillator ’ s frequency and duty - cycle could be adjusted if reference current source or capacitors in the circuit was adjusted . and the changes of temperature and voltage affect stabilize of the frequency little 此电路利用系统内部基准源产生的电流信号来对电容进行充放电,然后经过控制电路作用后,产生的输出振荡波形的上升时间和下降时间非常小,更接近理想矩形波形;通过调节基准源电流信号或者电容值大小,可调节振荡波形的频率和占空比,同时温度和电压的变化对振荡器输出波形频率稳定度的影响很小。
Since 1960 " , the methods for charactering time - frequency stability in time - domain have been in progress . the methods include allan variance , modified allan variance , time variance , hardamard variance , total variance , time interval error ( tie ) and maximum time interval error ( mtie ) , of which tie and mt1e are usually used for telecommunication network 自20世纪60年代以来，时间及频率稳定度的表征方法一直在不断的发展，有阿仑方差、修正阿仑方差、时间方差、哈达玛方差、总方差以及常用于电信网络的时间间隔误差( tie )和最大时间间隔误差( mtie ) 。
Then novel circuit structure and circuit topologies family of current source ac / ac converters with high frequency ac link , based on flyback converter , are proposed . the circuit structure which can transfer one unregulated sinusoidal voltage with high thd into another regulated constant frequency sinusoidal voltage with low thd , is constituted of input cycloconverter , high frequency storage transformer , output cycloconverter , input and output filter . the circuit topologies family include single four - quadrant power switch mode , push - pull mode , half - bridge mode , and full - bridge mode circuits 本文提出了基于反激flyback变换器的电流源高频交流环节ac ac变换器电路结构及其拓扑族，该电路结构由输入周波变换器、高频储能式变压器、输出周波变换器以及输入、输出滤波器构成，能够将一种不稳定劣质的正弦交流电变换成另一种同频率稳定的优质正弦交流电压；该电路拓扑族包括单四象限功率开关式、推挽式、半桥式、全桥式等四种电路。
Jinque co . has developed neo - generation reliable frame - structure ups , which is high frequency and on - line intelligent and whose height is 19 inchs . the product adopts cpu process , so it has excellent ability to calculating and accurately test every control point to guarantee reliability of quality . at the same time , due to the design of double - change power , the voltage and frequency are stable ; the product deletes all kinds of interrupted frequency and becomes power of sine wave to provide vital equipment with better power environment 金雀公司根据网络系统的电源要求，开发出新一代高可靠的19英寸机架式高频在线智能型gr系列ups ，采用cpu处理器，极强的运算能力，精确迅速地检测ups各控制点，由于采用双变换电源设计，供负载使用的电源电压频率稳定，滤除杂读的纯净正弦波电源，为重要的设备提供更佳的电源环境。
The definition of stability and repeatability of the laser frequency and factors affecting the stability of laser frequency were analysed . the normal methods used to stabilise frequency and produce double - frequency were explained . after analysing the working conditions and related parameters of the laser device , it was concluded that the laser tube should be put inside an insulating cover and an electric discharge tube with a bigger diameter and length , smaller wall thickness and a higher thermal conductivity coefficient should be chosen 分析了激光频率的稳定性、复现性的定义及影响激光频率稳定的因素；介绍了常见的稳频及产生双频的方法；分析论证了激光器双纵模热稳频的使用条件和有关参数的关系，得到结论是：应将激光管装在保温罩内；选用放电管直径及长度大、壁厚小、材料导热系数大的放电管。
