查询词典 frequency band

In chapter 4, the Newlands harmonic wavelet is improved and a new type of wavelet with better time-frequency characteristic is constructed. Frequency band of signal can be divided arbitrary with the improved harmonic wavelet so that the phenomena of aliasing are reduced. Several typical fault signals in Electromechanical System are analyzed with it. In addition to the improved harmonic wavelet in chapter 4, a new half-complex wavelet is presented to improve the complex wavelet, which is given by Chaari.O. A unilateral recursive algorithm is derived to improve the real-time characteristic. A parameter n is imported to make the time-frequency and filtering characteristics of it better and its ability of extracting fault feature is enhanced.

第四章通过对Newland谐波小波的改进构造频域紧支撑、时域性能良好的新型小波函数，可实现信号频带的任意划分，从而减少频带混叠现象，采用改进的谐波小波对多种典型的机电系统故障信号进行了分析；以Chaari.O复小波为基础构造了一个半复小波，从提高复小波算法的实时性出发，推导了半复小波单向递推算法，通过给原小波设置可调参数的方法，实现了一种能满足小波基本条件的复值小波，可以通过参数的调整调节小波滤波器在Hilbert空间的时频特性和相应的滤波性能，以加强半复小波对故障特征的提取能力。

The working load of engin e in plowing can be taken for stable and normal random load whose power spectrum peak value is below 2 Hz. The working load of engine in rototilling contains bo th periodic element whose fundamental frequency is rotating speed of the blade s haft and normal random load of which the parts of energy centers in fundamental frequency and others are distributed over wider frequency band.

证实了犁耕作业发动机的载荷可以认为是平稳的正态分布的随机载荷，其功率谱曲线的谱峰在低于2 Hz处；旋耕作业发动机的载荷是兼有随机成分和周期成分的动态载荷，其中周期谐波的基频为刀轴转速，随机成分一部分能量集中于基频以内，部分分布于较宽频率范围。

The main content of this dissertation includes: 1. Research on the theory of ultrasonic power supply, introduce its development process. On the basis of these, fix on the scheme of medical ultrasonic low-power supply. 2. According to the principle of modularized design, divide medical ultrasonic low-power supply into four parts. They are power amplify circuit, power control circuit, frequency automatic tracking circuit and matching circuit. Separately research on their theories and design their circuits and necessary programs, especially, effectively resolve the problem tracking the supersonic vibration system with a narrow syntony frequency bandwidth and a high swing. 3. The matching experiments gain good result, and prove that medical ultrasonic low-power supply is entirely up to the mustard on intellectualization, wide band of working frequency, steady output and high efficiency.

本文工作的主要内容包括： 1、研究了超声功率电源的原理，并回顾了它的发展过程，在此基础之上确定本文医用小功率超声电源的设计方案； 2、按照模块化的设计原则，将医用小功率超声电源的设计分解为功率放大电路、功率控制电路、频率自动跟踪电路和匹配电路等四个部分，分别研究了各部分的原理，在此基础之上进行了具体的电路设计和程序设计，尤其是有效地解决了对谐振频率带宽窄振幅高的超声振动系统的频率跟踪问题； 3、通过与超声振动系统的各项配合实验，取得了很好的实验结果，验证了医用小功率超声电源完全满足智能化、工作频带宽、输出功率稳定、输出效率高的设计要求。

The main peaks of the EEG power spectra were in delta and theta frequency range. In the stage of ethanol exposure, the rats exhibited much more act of attack than the control, the alpha waves of EEG decreased, while the delta waves increased. The EEG power spectra analysis showed the delta power increased and the theta power decreased. In the stage of ethanol withdrawal, the rats showed some withdrawal behaviors such as wet dog shakes, sniffing, groomingand tonic-clonic seizures for audiogenic stimulus. Spikes and spike-slow waves were found in the EEG. In power spectra analysis, the delta power decreased while the alpha and the theta power increased, the EEG frequency band moved to the high-frequency rang. These changes were found obviously on the sixth day and disappeared on the 1 Oth day after the ethanol was removed.

本研究发现：1、对照组大鼠行为无异常，伏核EEG以α节律为主，散在出现δ和θ节律；功率主峰在δ和θ频段范围，整个过程中未发现手术对伏核EEG及脑电功率谱有影响。2、在慢性饮酒过程中，大鼠攻击性行为增加，伏核 EEG的α节律明显减少，散在出现的高幅慢活动δ波逐渐增多，功率谱分析表明δ频段功率百分比明显增加，而θ频段功率百分比明显减少，总功率减少。3、停饮后，大鼠出现湿狗样抖动、打喷嚏等撤药综合症，并且高频声音刺激能引发惊厥；伏核EEG出现棘波和棘慢综合波，并持续增多，功率谱分析显示δ频段功率百分比 5 南京医科大学硕士学位论文逐渐减少，而0和以频段功率百分比逐渐增加，总功率增加。

Refining a variety of high-frequency plastic welding machines, high-frequency fusing machine, high-frequency metal heat treatment machines, wide-band ultrasonic machine, blister sealing machine, heat shrink packaging machine and other packaging equipment!

精制各种高周波塑胶熔接机，高周波熔断机，高周波金属热处理机，全频段超声波机，吸塑封口机，热收缩包装机等各种包装设备！

Wavelet modulus maxima with high frequency and low frequency coefficients were obtained firstly through multiscale decomposition of well logging data;then important wavelet coefficients were chosen according to the fusion principle where high frequency coefficients were taken as maximal absolute values and low frequency coefficients were selected by edge detection principle;finally alternating projection algorithm was applied to reconstruct the fusion curve.

首先对原始测井曲线进行多尺度分解，得到不同尺度下的小波低频系数和高频模极大值；然后选用高频系数取绝对值极大、低频系数采用边缘法的融合规则，选取重要的小波系数；最后利用交替投影算法重构融合曲线。

Experiments shows that it can detect the carrier frequency and the low frequency of modulation signal as expected, the resolution of the carrier frequency is 0.3Hz,the detecting error is within ±0.5Hz, and the resolution of the low modulation frequency is 0.07Hz, the detecting error is within ±0.05Hz.

实验结果表明该检测仪能很好地检测出信号的载频和信号的低频调制信息，其中信号载频的分辨率为0.3Hz，误差范围在±0.5Hz 以内，低频信息的分辨率可达0.07Hz，信号的误差在±0.05Hz。

A new frequency estimation algorithm for Time Domain Synchronization OEDM system is proposed, which utilizes the time domain circular characteristic of PN sequences to adjust frequency offset and then uses a variable step frequency scan scheme to estimate large frequency offset.

提出一种新的适用于TDS-OFDM系统的频偏估计算法，利用PN序列的时域循环特性进行预频偏调整，然后用变步长扫频进行大频偏的估计，定时同步之后再利用PN的时域循环特性进行细偏估计。

Below us Divider VHDL description of the source code for the completion of the clock signal CLK frequency of 2 hours, 4 frequency, frequency of 8 hours, 16 minutes frequency.

下面我们介绍分频器的 VHDL 描述，在源代码中完成对时钟信号 CLK 的 2 分频， 4 分频， 8 分频， 16 分频。

To review the basic terminology in data organization and data presentation 2 To learn frequency distribution and cumulative frequency distribution 3 To construct the graphical representations: histogram, frequency polygon, and culmulative frequency polygon

回顾数据组织及数据表达的基本用语。学习频数分布及累积频数分布。绘制如组织图、频数多边形及累积频数多边形等的图示。

Summary In copyright infringement cases,if the alleged infringer uses or even plagiarizes the copyrighted works or parts thereof,which causes no substantially adverse effect on the normal exploitation of the work,nor does it inflict any substantial damages to the right owner,the de minis doctrine should be applied to exempt the liabilities of the defendant and seek the balance of interests between the right owner and the general public embodied by the copyright law.

在侵犯著作权案件中，如果被控侵权行为人虽未经著作权人的同意，使用甚至抄袭了受著作权保护的作品或作品的片段，但若情节轻微，未对该作品的正常使用产生任何实质不利的影响，亦未对权利人的权利造成实质性的损害，则应适用&不计琐细原则&，免除行为人的责任，以寻求在权利人利益与著作权法所体现的社会公共利益之间的平衡。

This new product will become our best seller.

这个新产品会成为我们最畅销的产品。