查询词典 harmonics

An adaptive notch filter is presented to analyze integral and fractional harmonics of variable fundamental frequency.

摘要采用自适应陷波滤波器实现基波频率可变的多谐波(包含整数次谐波和非整数次间谐波)分析。

For example, to take a guess at tall odd order harmonics, draw an imaginary curve from the fundamental to the F3 and F5, and it's almost guaranteed that the F7 and F9 are going to fall close to where that curve extends.

例如，要采取高奇次谐波猜测，借助根本性的F3和F5一个假想的曲线，这几乎保证了F7和F9键将要下降接近如该曲线延伸。

When up to 31th harmonics are analyzed, the calculation time is only 1/82 of theat by the classical Gaussian elimination method.

对于一个周期值事先不知道，在一个周期内有100个采样点的非整周期采样，这个近似方法可使谐波分析的准确度由一般的DFT的10〓量级提高到10〓量级；当分析至31次谐波时，计算时间约为经典高斯消去法的〓，将能满足实际的工程需要。

Surrounded and lifted up by the storied past or the harmonics of hand-me-down fiddles, banjos, mandolins, hammered dulcimers and guitars, each hardtack generation has been inspired and nurtured by the melodic expression of an ancient mountain region – Appalachia.

包围而且被传说上有名者举起越过或者现成小提琴、班卓琴、曼陀林、被槌打的德西马琴和吉他的和声学，每个硬面饼世代已经被远古山区域－阿帕拉契山区的有旋律表达激发而且养育。

Based on the analysis of harmonic detection technology at home and abroad on the status and development direction of the foundation, Power harmonics of the basic theory and the detection algorithm.

本文在分析了国内外谐波检测技术的现状和发展方向的基础上，研究了电力谐波的基础理论和检测算法。

In sphere approximate, GPS/Gravity-BVP is Neumann problem over exterior spherical domains. Then the natural boundary reduction, suggested by Feng and Yu, is applied to deal with the three dimensional problems. By expansion in spherical harmonics, the natural integral equations of harmonic problems over exterior spherical domains are obtained. Meanwhile, a numerical method for solving geodetic BVP is developed.

在球近似下将GPS-边值问题转化为Neumann外问题，用自然边界元法进行自然边界归化，得到自然边界积分方程，再求自然边界积分方程的数值解，与其他边界元方法相比，自然边界元法的计算量大大减小，并且具有很好的逼近性质，能有效地处理奇异积分，是求解GPS-边值问题有效方法。

Results indicate that:(1) by using HANTS, the researchers could get the EVI/NDVI harmonic curves, the mean VIs and the amplitude of the harmonics which then were utilized in the identification of the cultivated land, and EVI appeared to be more precise, with the overall accuracies of 97.17% and 95.99% and Kappa coefficients of 0.7938 and 0.6518, respectively.(2) Multiple cropping index was extracted by counting the number of the curve's peak; and when the threshold of the peak value of the NDVI and EVI curves were set as 0.25 and 0.20, respectively, the fallow land could be well figured out.(3) From harmonic curves, some eigenvalues, such as time of the maximum growth rate, time of peak and the value of peak can be extracted, based on which the crop types can be primarily distinguished. And EVI still performed better than NDVI in this section.

结果显示：（1）利用傅立叶谐波变换得到的EVI和NDVI时间谱曲线的谐波余项及谐波振幅对耕地进行识别，从识别精度来看，EVI要优于NDVI，识别精度分别为97.17%和 95.99%，Kappa系数分别达到0.7938和0.6518；（2）通过计算时间序列曲线的波峰数能够提取耕地的复种指数，并且在EVI和NDVI曲线波峰阈值分别设为0.20和0.25时，休耕地能较为准确地被识别出来；（3）通过提取作物生长期内曲线的VI最大增长速率时间点以及峰值时间点等信息，作物种类能被初步识别，并且EVI较NDVI具有更强的识别能力。

How to measure harmonic effectively is necessary for improvement and optimization. The surveillance equipment for power quality, which can analyze the harmonics become more and more important in the low-voltage system.

如何准确有效的检测谐波是改善和优化电网电能质量的前提，带有谐波分析功能的电能质量监控装置在低压系统中呈现越来越重要的地位。

Keywords: Harmonics, active power filter, Fourier Algorithm, Harmonic analysis and measure, Harmonic prevention

谐波，有源滤波器滤波器，傅立叶变换，谐波分析测量，谐波抑制

Because the harmonic is harmful to the electric net and electrical equipment, it is very important to measure the harmonic accurately and restrain it. Some methods for harmonics measurement are proposed in these years.

由于谐波对电网及用电设备有诸多危害，准确测量谐波及抑制谐波就显得尤为重要。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失