查询词典 frequency band

The geometric detail is represented as the set of the local affine coordinates of the base surface and extracted effectively and efficiently in user specified frequency band of geometric signal.

通过基曲面上的局部仿射坐标，则可以得到与之对应的多分辨率几何细节表示，曲面的低频信息和高频信息易被用户所指定的频段分离。

When used in signal expansion, this model can give a relative constant error of approximation in a larger frequency band.

实现了采用此模型的匹配算法，并且通过实验对比了梯度法、相位法和新算法的性能

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

The information includes combustion, valve-open and valve-close information. But this signal also contains interfering noise, like exhaust noise and other noise eradiated from the other part of the diesel engine, and the frequency composition of useful signal and interfering noise are largely overlapped in the frequency band under 20 KHz.

但是提取的缸盖噪声信号中也含有柴油机工作时产生的排气噪声和机体其它部位辐射噪声等干扰信号，且干扰信号与有用信号的频率成分在20 kHz以下的频带内重叠在一起。

Then based on CWMS, we propose a new method to enhance the resolution of seismic traces. Firstly, we divide the seismic signal into proper segments by Gabor molecule-windows adaptive to the signal, where each segment is regarded stationary, and then transform it into the Gabor domain. Secondly, we deal with the amplitude spectrum for each segment to expand the frequency band of the spectrum in the Gabor domain. Finally, taking inverse Gabor transform on modified time-frequency coefficients, we get the high-resolution signal.

然后基于变子波模型，提出了一种新的提高地震记录分辨率的方法：第一步，用自适应于地震记录的Gabor分子窗把地震记录恰当地划分成若干片断，每段内信号近似平稳，然后将地震记录变换到时间-频率域；第二步，在变换域对每个分子窗内信号的振幅谱进行处理以拓宽频带；最后把处理后的时间-频率域函数反变换回时间域得到提高分辨率后的结果。

Ltd, which was founded in 2002, designs and manufactures a series of passive devices, such as filters, duplexers, couplings and multi-frequency band mixers in communication frequency bands of DCS, GSM, CDMA and 3G.

南京震宇通信技术有限公司成立于2002年，创业以来，公司先后在DCS、GSM、CDMA、3G通信频段内设计生产了一系列滤波器、双工器、耦合器、多频合路器等无源器件。

Series digital geophones are mainly used in petroleum exploration. The series have wide frequency band,high spurious frequency and all parameters are controlled within 5%.

系列数字地震检波器主要用于石油勘探，具有宽频带和较高的假频，各参数指标容允差均在5%以内。

The low material cost as well as the high product stability is two important factors to design the antenna of Bluetooth headset. Base on the HFSS simulation results, the meander line monopole antenna is applied for the frequency band 2402MHz~2480MHz of Bluetooth headset to design its antenna. The characteristics of the different meander line monopole antennas as compared under there different frequency bands.

本篇论文针对蓝芽系统的无线耳机天线，以节省材料成本以及增加产品稳定性为考量因素做为设计天线重点考量因素，依据应用曲折型单极天线模拟结果於蓝芽频段2402MHz~2480MHz之天线设计测试，并与不同曲折样式之天线在不同频宽进行性能比较。

Using natural frequency ratio and damping ratio as design variables, constructing an objective function with the peak values of dynamic magnification factor and the dynamic magnification area of the main system in the whole frequency band, the optimization problem is built.

建立了以固有频率比和阻尼比为设计变量，以振幅动力放大系数函数的多个峰值和整个宽频带下面积构造目标函数的优化问题。给出了两个自由度减振器参数的优化计算实例。

a novel miniaturization bow tie rfid tag antenna is proposed based on the triangular sierpinski fractal microstrip.the port characteristics of the proposed antenna are presented by simulation.at the same time,the resonance frequency,the radiation pattern and the efficiency of the sierpinski tag antenna is given.the results of the simulation show that multiple frequency band can be obtained by varying the dimensions of the fractal structure.hence this kind of antenna can be used into the rfid tag antenna very conveniently.

摘 要：基于三角形sierpinski微带分形贴片，提出了一种新型的小尺寸领带结rfid标签天线设计。通过仿真，给出了该分形天线的端口特性，同时给出了该领带结型sierpinski标签天线的谐振频率、方向图以及天线效率。结果表明，采用不同维数的分形结构，可以实现多频段的工作特性，因而该天线可以很方便地应用于rfid电子标签中。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。