查询词典 frequency analysis

At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.

一种DFT扩频的广义多载波系统的SINR估计方法，其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系，然后根据信道频率响应、信道噪声方差和均衡方法，设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数，再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差，再计算有效信干噪比，如此以实现对广义多载波传输系统的有效信干噪比的准确计算，该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。

On the basis of analyzing the oscillatory frequency of crystal oscillator , the general expression of the frequency deviation of crystal frequency modulation oscillator is de rived .

本文在分析晶体调频振荡器振荡频率的基础上，得出了晶体调频振荡器频偏的一般表示式，最佳负载条件下的频偏设计公式和调制级有电流串联负反馈时的频偏设计关系式。

Results indicated there were significant seasonal and spatial distribution characteristics. Drought occurred in high frequency at the stage of tasselling to silking and thereafter. Drought frequency obviously increased with backwards shift of growth stage. Light drought happened in higher frequency than medium and severe drought.

结果表明，湖南春玉米生长季节内干旱呈现明显的季节性和空间区域分布特征：干旱频率较高的时段主要在玉米抽雄－吐丝阶段及其后的生育阶段，且随生育期后移干旱频率明显增加，以轻旱程度为主。

The results show that, under each drip irrigation treatment before the tasselling stage of spring maize, the fluctuation of average soil water content and soil matric potential at different soil depthes are comparative low under high frequency drip irrigation treatment, and the HDI can hold stable soil water content. The drip irrigation can obviously delay the effect of air temperature on the soil temperature, which was influenced by irrigation process, soil water content and crop growth stages. In addition, the irrigation frequency affects the spring maize root distribution in the soil, and the HDI improves the probability of root distribution in upper soil(0~40 cm). The yield difference of spring maize for irrigation frequency treatments is not significant under the typical field irrigation model combined irrigation with precipitation.

试验结果表明：在春玉米抽雄期以前阶段实施的滴灌各处理中，高频滴灌下土壤平均含水率和不同深度处的土壤基质势波动幅度较小，高频滴灌下土壤水分能保持在一个比较稳定的范围；土壤温度受灌水过程、土壤含水率及作物生育阶段的影响较明显，滴灌能显著延迟气温对土壤温度的影响；灌水频率对春玉米根系分布存在一定影响，高频灌溉能显著促进春玉米根系在上层土壤(0～40 cm)中的分布；此外，在这种典型的灌溉和降雨相结合灌溉模式下，不同灌水频率下玉米产量差异不显著。

At present, the Company electromagnetic vibration feeder, air hammer, level gauge, solenoid valve and control device, screw feeder, belt conveyor, bucket elevator, dust collector, zero speed switches, proximity switches, high-frequency coil , electromagnetic vibrators, vibration hopper, vibration controllers, marking electromagnet, power conditioners, heating units, heating the first, high-frequency cable, high-frequency transformers, ignition transformers and other products have been sold all over the country, has been unanimously praised users .

目前，本公司电磁振动给料机、气锤、料位计、电磁阀及控制仪、螺旋给料机、皮带输送机、斗式提升机、除尘器、零速开关、接近开关、高频线圈、电磁振动器、振动料斗、振动控制器、打标记电磁铁、电源调节器、加热单元、加热头、高频电缆、高频变压器、点火变压器等产品已销往全国各地，得到了用户一致好评。

When the frequency is 15Hz and number of ampere turns is 20kA·turn, relative intracrytalline solubility of alloy elements (for Zn, Mg and Cu the solubility are 68.8%, 76.0% and 45.0％, respectively) is the highest; when the frequency is 15Hz and number of ampere turns is 20kA·turn, Vicker hardness is the highest of Hv160; when the frequency is 25Hz and number of ampere turns is 20kA·turn, ultimate tensile strength is the highest of 324MPa.

频率为15Hz，安匝数为20kA·turn时， Zn、 Mg和Cu元素相对溶质固溶百分数最高，分别为68.8%、 76.0%和45.0％；频率为15Hz，安匝数为20kA·turn时，锭坯维氏硬度最高为Hv160；频率为25Hz，安匝数为20kA·turn时，抗拉强度最高为324MPa。

A silent communications system in which nonaural carriers, in the very low or very high audio-frequency range or in the adjacent ultrasonic frequency spectrum are amplitude- or frequency-modulated with the desired intelligence and propagated acoustically or vibrationally, for inducement into the brain, typically through the use of loudspeakers, earphones, or piezoelectric transducers.

在一个无声的通讯系统中，一个非常低或者非常高的音频，或者接近超声波的频率，其波幅或者频率被调节到具有相当被理解能力并以合适的振动方式或者以听觉传输的方式来刺激一个昏睡者的大脑。典型的装置是用扬声器，耳麦，或者变压器。

Based on rail/wheel reaction and track/bride reaction theory and systems engineering theory, new vehicle-track and vehicle-track-bridge system dynamic models are established and discussed in details, including ballast track model and ballastless track model. The characteristics of the models are:(1) vehicle-track and vehicle-track-bridge system dynamic models are coupled in vertical and lateral;(2) track vibration on bridge is taken in account, track on bridge is considered as one or two layer continuous-point supported rail model, according to actual track structure, interaction between vehicle and bridge transfer from track structure;(3) three type of ballastless track models (tieembanked, elastic-tie-block, slab track) are presented;(4) models reflect the main feature of actual vehicle, track and bridge structure, the response computation frequency of models is relatively broad, which can be applied to analyze both low frequency and high frequency vibration.

基于轮轨相互作用和线桥相互作用特点，本文从系统工程角度出发建立了车辆、有碴轨道和无碴轨道、简支箱梁桥垂向和横向耦合系统动力分析模型，该系统模型具有以下特点：（1）车线、车线桥体系均考虑为垂向、横向耦合振动系统，车线间通过轮轨接触几何关系耦合，轨道与桥梁间通过轨道与梁体间的力与位移协调条件耦合；（2）充分考虑桥上线路在车线桥系统中参振作用，根据桥上线路轨道结构特点将桥上轨道结构模型具体化，即对桥上轨道结构视为多层支承体系，车桥间的动力作用通过轨道结构来传递；（3）建立了三种形式无碴轨道动力分析模型，即长轨枕埋入式、弹性支承块式和轨道板式无碴轨道模型；（4）系统模型详细，分析频带宽，适用范围较广。

When the digitalsignal carries on the long distance transmission, the high frequencycomponent weaken increases along with the distance increases, theelectric cable median line also advances to the betweenelectromagnetic radiation along with the frequency intensifies, thusthe clipped wave transmitting range and the transmission quality,simultaneously in the channel often also exists separates the directcurrent electric capacity and the coupling transformer, they cannottransmit the direct component and have a bigger weaken to the lowfrequency component, therefore high frequency and low frequency arepartial regarding the common channel is limited.

当数字信号进行长距离传输时，高频分量的衰减随距离的增大而增大，电缆中线对之间的电磁辐射也随着频率的增高而加剧，从而限制信号的传输距离和传输质量，同时信道中往往还存在隔直流电容和耦合变压器，他们不能传输直流分量及对低频分量有较大的衰减，因此对于一般信道高频和低频部分均是受限的。

In tested frequency range, the damping ratio keeps constant under different vibration frequency, which is verified again that the concrete is not the ideal sticky elastic material whose dissipation characteristic is correlative with frequency.

在实验的频率范围内，不同振动频率下的阻尼比近似保持常数，再次证实混凝土并非耗能特性与频率相关的粘弹性材料；砼构件的动刚度随振动频率变化不大，表明其力学参数无明显频变特征。

Molecular Distillation is a kind of high vacuum distillation method, which is suitable for the separation of high boiling, heat sensitivity and viscidity products.

分子蒸馏技术是一种在高真空条件下进行的连续蒸馏过程，适合于分离高沸点、热敏性及具有生物活性的混合物。

They are to the Noughties what yuppies were to the Eighties .

那在六十年代是时髦的，但在八十年代肯定是过时了