频率

Based on the analysis of error characteristics and performance effect of the mostly used crystal oscillator, a method to simulate the frequency error of crystal oscillator is proposed. The major idea is to determine the Allan variance parameter of each main stochastic error component at the given sampling interval at first, then to deduct a set of corresponding frequency error series and superpose them together.

该文对在GPS接收机中使用最多的晶振的误差特性和性能影响进行了分析，在此基础上提出了一种模拟晶振频率误差的方法，即首先确定晶振在给定取样时间间隔上各主要随机误差成分的Allan方差参数，由此反演产生相应的各项晶振频率误差模拟序列并进行叠加。

The working frequency is equal to or less than the permissible error limit of measurement frequency of the resistance box..

电阻箱的工作频率等于或低于测试频率上限时的最大允许误差。

To investigate high-accuracy frequency measurement,the measurement error of the phase detection method is analyzed.

针对高精度的频率测量，分析了相位检测法的测量误差，根据分析结果提出并实现了一种基于FP-GA实现的频率测量方法。

To further understand and correctly master the notion of marginal spectrum in Hibert-huang transform, the linear property of marginal spectrum is demonstrated, an mistake to the notion of marginal spectrum in some documents is pointed out, and a new viewpoint about the essential difference between marginal spectrum and Fourier frequency spectrum is put forward by which the amplitude of Fourier frequency spectrum only represents the probability that a frequency objectively exists in a signal while the amplitude of marginal spectrum decides whether a frequency objectively exists in a signal.

为了深入理解和正确掌握希尔伯特－黄变换（Hilbert-Huang Transform，简称HHT）中的边际讲概念，证明了边际谱的线性性质，指出了文献中对边际谱概念的一种误解，提出了边际普与Fourier频谱之间本质区别的一种的新观点，即Fourier频谱的幅值只能反映频率在信号中实际存在的可能性大小，而边际谱的幅值则能真实反映频率在信号中是否存在。

A backscatter fiber is used to expand the width of laser pulse. A locking filter is added to dual F-P etalon. Photo Multiplier Tube is used to detect the intensity of light and a frequency tracking circuitry is designed.

使用散射光纤对激光脉宽进行扩展，在双通道标准具的基础上增加专用于频率跟踪的通道，使用光电倍增管检测光强，设计制作了基于采样的频率跟踪电路。

After the mathematic model of spatial spectrum analysis was introduced, interharmonic signals can be transformed to spatial signals received by linear sensor array through Euler\'s formula or Hilbert transform. The number of sinusoidal components of the interharmonic parametric model was corresponding to the source number of transformed spatial signals, and the frequencies of sinusoidal components were corresponding to that of transformed spatial signals.

3介绍了空间谱分析的数学模型，证明了间谐波信号经欧拉公式或希尔伯特变换后可以转变为空间线性阵列接收的空域信号，正弦成分数对应空域信号源数，正弦成分频率对应空域信号频率。

BUse the experimental method to examinate the proposed relation obtained from the numerical simulation. The state of simulated degradation is mainly expressed by the parameters such as speed of P wave, the thickness of upper layer of concrete and interval of cracks.

另一为探讨实际量测混凝土版劣化后其反应频谱各振幅尖峰频率值之关系，并与数值模拟分析之结果相互验证，模拟劣化状况主要是以P波波速、混凝土上层厚度与裂缝间距作为变数，进而探讨对振幅频率的影响。

Firstly, the natural frequencies and normal mode shapes of the fluid-conveying pipe with zero fluid velocity (i.e. U=0) were determined with the transfer matrix method. Next, these natural frequencies and normal mode shapes were used to derive the equation of motion for the fluid-conveying pipe with fluid velocity U.neq.0 by using the expansion theorem. Finally, the free and forced vibration responses of the pipe with flowing fluid were obtained by means of the Jacobi method and the Newmark direct integration method.

首先吾人使用转移矩阵法来求取一流速等於零(即U=0)、跨距数为N之流体输送管的自然频率及其所对应之正规化振态，然后利用振态重叠法原理来推导流速不等於零(即U.neq.0)时，整个流体输送管在外力作用下的运动方程式，最后再以Jacobi法及Newmark直接积分法来计算该水平流体输送管的自然频率及强迫振动反应。

The frequency of regeneration and the mean number of shoots per explant were decreased with the increase of Ca〓 concentration.

无Ca〓培养基上的不定芽再生频率最高，随着Ca〓浓度的增加，再生频率及单位外植体芽数降低。

The number of strokes per flash does not show a exponential decay distribution.

结果表明，每次地闪回击数频率分布并不表现为简单的指数衰减特征，回击数在 5次以下的各回击数出现频率几乎相当，单次回击地闪的比重只有约 1 5 %。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。