查询词典 frequency channel

The wavelet time-frequency properties of the uncracked rotor and the cracked rotor were discussed by the continuous wavelet time-frequency analysis algorithm. A new algorithm using the wavelet time-frequency analysis algorithm to detect the crack was proposed. The influence of the sampling frequency on the wavelet time-frequency analysis algorithm was analyzed through the numerical simulation research; the valid sampling frequency was presented.

利用连续小波时频分析方法，讨论了裂纹转子与无裂纹转子的小波时频特性，提出了利用小波时频分析方法识别裂纹的新方法；数值仿真研究了采样频率对小波时频分析方法的准确性和有效性的影响，并给出了建议性的采样频率。

When microgrid is operated in islanded mode, VSGs can be divided into non-frequency regulation units and frequency regulation units, the former can generate power and participates in primary frequency control according to dispatching to mitigate system frequency deviation due to disturbances; the latter can offer referential voltage of microgrid and use secondary frequency regulation to implement no-error frequency control.

微电网孤岛运行时，将虚拟同步发电机分为非调频发电单元和调频发电单元，前者既能按照功率调度指令发电，又能参与一次调频，缓解扰动情况下系统频率的波动，后者提供微电网参考电压，并利用二次调频实现频率的无差控制。

The number of the frequency division of the method and the circuit structure thereof do not influence the highest frequency of the working circuit. The normal work of the frequency division circuit can be at a comparatively high clock frequency, and the clock frequency division can be realized in the manner of cascade connection of the frequency division circuit so that the scale of the circuit realization can be properly reduced.

本发明所述方法及其电路结构的分频数大小不影响电路工作的最高频率，可以使分频电路正常的工作在相对很高的时钟频率，而且可以通过分频电路级联的方式实现时钟分频，从而可以适当减小电路实现的规模。

The Company is responsible for people at high-frequency machine Through more than ten years of research and design, has been developed to create a series of applicable to all types of plastic / PVC, rubber, leather, Blister packaging high-frequency welding / fusing machine; trademark high-frequency equipment machinery, high-frequency metal weld / heat treatment machine ; high-frequency pipe machine; high-frequency synthetic resin preheating aircraft and other special plastics processing machinery.

本公司负责人在高周波机器上通过十余年的研究和设计，现已开发，制造出一系列适用于各类塑胶/PVC，橡胶，皮革，吸塑包装等高周波熔接/熔断机；高周波商标专用设备机械，高周波金属熔接/热处理机；高周波制管机；高周波合成树脂预热机以及其它特殊塑胶加工机械等。

Then, it is tuned to a channel frequency of one of a digital cable channel and an analog cable channel based upon a value of the details channel source field.

然后，根据具体频道源字段的值，将其调谐到数字有线频道和模拟有线频道之一的频道频率。

Through simulation and computation, some critical values to contral interferences are obtained. These values have directive significance to the design and deployment of WRAN.(4) New methods to measure and analyze spectrum aredevelopedAccording to the shortages of previous spectrum measurements, new methods to measure spectrum occupancy in wide-band and multi-point synchronously is proposed in this dissertation, and the tests last a whole week; the relativities of licensed services are considered when test points are selected. More importantly, data mining and in-depth analysis are carried out with the huge amounts of test data, and a channel analysis method using Channel Vacancy Duration and Service Congestion Rate are proposed. The spectrum relativities of 3-dimension in time, space and frequency are researched also. The correlativity between channel state and history information is discoved, and which will provide the scientific basis to channel modeling, spectrum analysis and decision of CR users.

4提出了频谱测量与分析的新方法针对以前频谱测量工作存在的不足，本文提出了多点同时广域频谱测量方法，测量工作持续了一周的时间，同时考虑了测量地点的选取和频谱授权业务之间的相关性；对测量得到的海量数据进行了数据挖掘和深度分析，提出了使用信道空闲时间(Channel VacancyDuration，CVD)和业务拥塞率(Service Congestion Rate，SCR)进行信道分析的方法，研究了频谱之间的时间、空间、和频率三维立体的相关性，发现了信道状态和历史信息的关联性，为CR用户的信道建模、频谱分析和决策提供了科学的理论依据。

The method includes following steps:(1) initial frequency selection;(2) based on modulation mode adopted, the sending end carries out symbol mapping, changes signal spectrum based on label information of sub channel, and sends signal in time domain;(3) based on label information of sub channel, the receiving end carries out equalization for received signal, demodulates signal and accomplishes judgment;(4) carrying out channel estimation or prediction, the receiving end obtains updated information of signal state, and determines whether label information of sub channel is needed to update based on self-adapting judgment rule.

本发明提供了一种移动宽带信道中的自适应选频分块传输方法，该方法包括以下步骤：(1)初始选频；(2)发端根据所采用的调制方式进行符号映射，根据子信道标记信息改变信号频谱，并发送时域信号；(3)收端根据子信道标记信息对接收信号进行均衡，解调信号并完成判决；(4)收端进行信道估计或预测得到更新的信道状态信息，根据自适应判断规则，判断是否需要更新子信道标记信息。

Consequently the beam transmission problem is solved well. The general design curves of microwave plasma drift tube are developed by the theory and they can be used for development of the plasma microwave devices. Ion channel, as a important phenomenon in the interaction between electron beam and plasma, is first introduced into the study of PASOTRON, to replace the concept'plasma channel'used in general plasma microwave devices. A model is created to describe the channel performance. The channel is not stable, it is oscillatory and the oscillation frequency is larger than that of plasma.

作为电子束与等离子体相互作用的一个重要现象，本文首次将离子通道的概念引入到了PASOTRON的研究中，以区别常规的等离子体通道概念，并通过建立的模型推出离子通道并非一稳定规则的通道，而是具有振荡特性，振荡频率高于等离子体频率，推出了当满足一定条件时束外可能没有电子而成为纯的离子通道，这种状态对微波器件有重要的价值。

Spectral efficiency equations are derived for both systems with and without channel prediction. Numerical results show that systems with channel prediction can get maximum spectral efficiency while systems without channel prediction but chosen optimum packet length can get suboptimum frequency efficiency, which is inversely proportional to Doppler frequency.

推导了信道预测和没有信道预测的自适应调制系统的频谱效率公式，分析结果表明对于自适应调制系统，信道预测的系统频谱效率是最优的，非信道预测系统根据信道情况选择最优帧长可以获得该系统的最优系统频谱效率，但它是低于信道预测的频谱效率的，而且是随多普勒频率的增大而逐渐减小的。

to reduce the impact of carrier frequency offset in ofdm system,this thesis designs a new carrier frequency offset estimation scheme for ofdm system.the carrier frequency offset estimation includes acquisition and tracking.we adopt variable step size adaptive algorithm.the acquisition range of the proposed algorithm is as large as one half of the overall signal bandwidth.through this method we can not only avoid the feedback by using forward error correction,but also reduce the times of complex multiplication in order to reduce the power consumption of the system.this algorithm not only has low complexity and fast convergence nut also can improve the demodulation performance of ofdm system.computer simulation illustrates the superior performance of the proposed algorithm with regard to estimation accuracy in both awgn channel and multi—path channel.

摘 要：为了减小正交频分复用系统受频率偏差的影响，在ofdm系统中设计了一种新的载波频偏估计算法。频偏估计包括跟踪和捕获两个阶段，文中采用变步长自适应算法来进行跟踪，这个跟踪算法的捕捉范围是整个信号带宽的一半。通过此方法，不但可以利用前向纠错的方式来避免反馈，而且可以缩减复数乘法的次数以降低计算复杂度和系统功耗。该方法运算复杂度低，并具有较好的收敛性，能改善odfm的解调性能。从计算机的仿真效果可以看出无论是在awgn信道上还是在多径信道上都表现出了卓越的性能。

Looking to bounce back from defeat against Cesena last weekend, the Calabrian boss will be sticking to his tried and tested 4-3-3, with Lopez and Sedivic joined up front in Giampaolo's absence by either Nanni or Plasmati.

鉴于上周末对切塞纳的比赛中反败为胜，这支南方球队将会更坚持其一贯而有效的4-3-3阵型，洛佩斯和塞德维奇将取代受伤缺席的詹保罗，和纳尼或者帕斯马蒂中的一个搭档锋线。

Meanwhile, their exposure to the more freewheeling ways of the West broadened dramatically.

另外，西方较自由的生活方式对年轻人的影响增大。