查询词典 radio-frequency spectrum

In contrast, the frequency-domain method transforms the time-frequency convolution into product operation in multiple frequency bands, thus has simple com putation and fast speed. As such, it has become a mainstream method for blind deconvolution.

相比之下，频域方法将时频卷积变换为多个频率段上的乘法运算，运算简单，速度快，因此成为盲解卷的主流方法。

This paper introduces eight methods of tlme-frequency analysis, such as Hilbert transform, Hilbert-Huang transform, sine curve fitting, Ricker wavelet matching, short time Fourier transform, wavelet transform, S transform and Cohen methods, This paper explains the merits and defects of those methods from the time resolution, frequency resolution and the adaptive ability of multi-frequency signals.

本文介绍了Hilbert变换、Hilbert—Huang变换、正弦曲线拟合、雷克子波匹配、短时傅立叶变换、小波变换、S变换以及Cohen娄这八种方法，并从时间分辨率、频率分辨率，以及对多频率成份信号适应能力等各方面阐述了各种方法的优缺点，对其中的一些方法结合了理论记录进行了试算，进一步阐述了这些方法的长处和不足之处。

Ricker wavelet whose predominant frequency is 200Hz was chosen as the exciting wave, and the character parameters (predominant amplitude, predominant frequency and frequency bandwidth) of its reflected wave were calculated.

选择主频为200Hz的雷克子波，理论计算原始地震反射波的特征参数（主振幅、主频率、频带宽度）。

Thist paper chooses 90 groups of "Tong_su_yi_xu synonymic words" from "Modern Chinese dictionary ", and divides them into three kinds according to the interpretation method in the dictionary, regards web page of Sohu website as the platform, us.es the search engine to carry on the search of the word , count the frequency that every group"s word appears , and rejects artificially the mistakes appearing in all web pages that can be opened, language fact presented in observation post then carefully (namely the example sentence with this word appearing in the webpage), and find that the 90 groups of "Tong_su__yi_xu synonymic words" except that the meaning of a word is the same, have quite a few of at frequency of utilization and concrete usage for difference: Because people"s use habit and word use the difference on to cause the appearance frequency of the word analogous to or with a wide gap, because of word-building ability, the word collocates, the word overlaps or the language usually overlaps, linguistic context of area and times , the meaning of a word that the word appears are abstract and concrete, semanteme is laid particular emphasis on, the morphological feature-change, etc.

本文从《现代汉语词典》中选取90组同素异序同义词，按词典中的释义方法将其分成三类，以搜狐网站的网页为平台，运用搜索引擎进行词语的搜索，统计下每组词语出现的频率，并将所有能打开的网页中出现的错误进行人工干预，然后仔细观察所出现的语言事实(即网页中出现的含有该词语的例句)，发现这90组同素异序同义词除了词义相同之外，有相当一部分在使用频率和具体的用法上还存在着差别：由于人们的使用习惯和词语使用上的差异造成词语的出现频率相当或者相差悬殊，又因为构词能力、词语搭配、词语重叠或语素重叠、词语出现的区域和年代语境、词义抽象与具体、语义侧重、词性变化等方面的差异造成词语使用上的区别。

We select the weighting matrices in the frequency domain, and then design the controller in the state space. The cases that the plants consist of both low-frequency parameter perturbations and high-frequency unmodelled dynamics have also been considered.

文中考虑一大类存在低频摄动和高频未建模动态的情形，给出了鲁棒控制设计中兼顾闭环动态特性和干扰抑制时的加权阵选择方法与具体步骤。

In this paper,the necessity of frequency tracking in ultrasonic cleaning equipmens is discussed.Based on introduction on the principle of the mian circuit of the ultrasonic power supply for cleaning equipmens and the principle of PLL,the output frequency of 74HC4046 is changed by a single chip measuring the phase difference between volage and current.The software of adaptive tracking technique with varied frequency steps is completed.

讨论了超声波清洗机中自动频率跟踪的必要性，在介绍超声波清洗机的主电路原理、PLL锁相环原理的基础上，利用单片机检测超声电源负载的电流、电压的相位差，从而改变74HC4046 的输出频率，完成了变步长频率跟踪软件设计。

As the same section is concerned, near the bottom the maximum value of frequency appear within 1mm of bubble size, towards the water face this value tend to decrease, yet the corresponding size turns to increase; in the same time, the frequency is concentrated near the bottom and deconcentrated near the water face; under the experiment condition, the maximum frequency of the total section approximately appear at 0.5mm size; mean bubble size access 0 at bottom and increase acceleratively towards water face where tend to be infinite; total number increase during developing of aeration, and become steady when reach wholly developed area; on the same section, the total number in unit time tend to increase at first and decrease then, along the water depth.

对于同一断面，靠近槽底的测点气泡个数分布最大值出现在气泡尺寸小于1mm的范围内，朝水面方向各测点气泡个数分布最大值呈减小趋势，而其对应尺寸则呈现变大趋势；在靠近槽底，个数分布表现得比较集中，而在水面附近气泡个数分布曲线表现得低而平缓；实验条件下，整个断面上的气泡个数分布的最大值大体上出现在尺寸为0.5mm的地方；气泡平均尺寸在槽底处接近于0而朝水面方向迅速增大，且越接近掺气水流的水面，增加速度越快，最终趋于无穷大；气泡总数在掺气发展区内是沿程增加的，当掺气水流发展到一定程度后气泡总数就基本保持不变了；在同一断面上，各测点单位时间内的气泡总数随高度呈现出先增加后减小的趋势。

Demodulates the FM modulated signal Y at the carrier frequency Fc. Y and Fc have sample frequency Fs. FREQDEV is the frequency deviation of the modulated signal.

Josephus 问题的解答。n个孩子围成圆圈，选任一个数m，从第一个孩子开始数，数到m停止，这个孩子离开，再从第一个开始数，直到剩下一个孩子。

The FEM, whose process is very *** and is fit to deal with complex boundary condition, is used to simulate the frequency-domain IP. Studying the characters and laws of IP\'parameters under different measuring devices and undulate topography will provide scientific references and basis and reduce the multiplicities of interpretation. It is will be an attempt and exploration.Because of the frequency of the exciting currents is usually between 10-2～102 Hz, the vector A can be seen is not change with the time and the EM effect can be ignored in the low frequency.

双频以及伪随机三频激电法以它特有的轻便、快捷、高效率等特点在有色金属矿躲勘探领域里获得了广泛的应用，运用有限单元法的推导过程简单、适合处理复杂几何外形等特点来对双频以及伪随机三频激电法进行正演数值模拟，分析和研究了激电参数在不同丈量装置、模型参数和起伏地形情况下的特点和规律，为后续的资料解释提供科学的依据和参考，为减少地球物理中的多解性做一些有益的探索和尝试。

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。

Alternatively, the con- trollers can use the synchronous rectifier itself or loss- less inductor current-sensing methods to provide overload protection with lower power dissipation.

另外，康威特罗勒斯可以使用同步整流器本身或亏损减少电感电流检测方法，以提供低功耗过载保护。

Mr. Dauber's other Schatz hangs in his home movie studio.

多伯把沙兹的另一件作品挂在家里的电影室。