基本环路

Building of the operation rules of curl and divergence for vector field in R 3 space;2. Analysing by mathematics and the concepts of flux and curl , we can get the differential form of gauss s theorems in electrostatic field and ampere s cycle theorem in electrostatic field.

电动力学中的内容一般是从电磁学最基本的实验规律出发，由静电场中的库仑定律得到静电场的高斯定理和环路定理，利用通量与散度、环流与旋度的关系，得到静电场的高斯定理和坏路定理的微分形式。

The mutual inductance of the equivalent circuit, coupling coefficient, quality factor of the DR and microstrip coupling model have been discussed.

本文分析了振荡器的基本原理，介绍了振荡器的两种基本模型；给出了应用广泛的环路增益公式的推导过程，并提出了新的环路增益公式；讨论了振荡器相位噪声的线性化模型；介绍了锁相环的基本原理，分析了锁相环各部分电路相位噪声的传递函数。

The gainof the basic amplifier when the feedback network is not present is called the open-loop gain,a,of the amplifier.

基本的放大器的获取当反馈网络不是存在称开放环路的获取， a，放大器。

Often divided into two types:(1) sine wave oscillator, according to the network oscillation frequency of the different loop selected further divided into RC sinusoidal oscillator, LC sinusoidal oscillators, quartz crystal oscillators, voltage-controlled oscillator, voltage-controlled crystal oscillator and other forms;(2) non-sinusoidal oscillation device, also known as relaxation oscillator, is the use of capacitor charging and discharging and active device (transistor, FET, single-junction transistor, etc.) to generate the pulse-off square wave, rectangular wave, triangle wave, sawtooth wave, or these basic waveforms synthetic waveform and its frequency by the LC time constant charge and discharge circuits to decide.

常分两大类型：（1）正弦波振荡器，根据振荡环路中选频网络的不同，又分为RC正弦波振荡器、LC正弦波振荡器、石英晶体振荡器、压控振荡器、压控石英晶体振荡器等多种形式；（2）非正弦波振荡器，又称张弛振荡器，是利用电容充放电及有源器件（晶体管、场效应管、单结晶体管等）的通断来产生脉冲方波、矩形波、三角波、锯齿波或这些基本波形的合成波形，其工作频率由LC充放电电路的时间常数来决定。

A digital servo system for rubidium frequency standards was designed with microcontroller unit,ADC and DAC.

分析了铷频标内锁频环路相敏检波基本原理和数字伺服的基本方法。

A kind of concise nalytic-graphic approach for singular position analysis of complex multilooped planar mechanisms was put forward,I.e,firstly,let the mechanism be deconposed into basic kinematic chains,then deduce the singularity conditions of these BKC and lastly determine the singular position of the mechanism from the corresponding singular geometric figure.

提出了复杂多环路平面机构奇异位置分析的一种简明的分析图解方法，即先将机构分解为基本运动链，再导出基本运动链的奇异性条件，后由其相应的奇异几何图形，解出其机构的奇异位置。

First of all, the history of phase locked technology and the actuality of researches on it are introduced. Then, beginning with the fundamental principles of a phase-locked system, we build the mathematical model based on the architecture of the traditional analog PLL, and afterwards investigate some of its characters such as tracking, acquisition, noising, and stability. The system parameters are developed at the same time, and some universal conclusions on the theoretical analysis of PLL are reached.

论文首先对锁相技术的发展历史和研究现状做了简单介绍，然后从锁相系统的基本工作原理引入，以传统模拟锁相环的结构为基础，分析了锁相环的数学模型，并以此为出发点对锁相环的跟踪性能、捕获性能、噪声性能以及稳定性等各种性能进行了深入的分析，对环路的各项参数指标进行了详细的推导，得出了锁相环数理分析的普遍结论。

Reportedly, the current campaign to keep the original trees in the fundamental basis of the first large-scale use of color, were plants in the different sections of a different loop flowering shrubs features Rudong side door to Dongzhimen sections for Yuyemei flowering shrubs, Dongzhimen to Deshengmen sections flowering shrubs to safflowers Tze Wei.

据介绍，这次整治在基本保留原有大树的基础上，首次大规模使用色块、地被植物，在环路的不同路段形成不同的花灌木特色，如东便门至东直门路段花灌木为榆叶梅，东直门至德胜门路段的花灌木为红花紫薇。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。