查询词典 interference spectrum

The analysis shows that the reflection spectrum is the multiple beams interference, and the coupling ratio is similar to the reflection coefficient of Fabry-Perot cavity. The larger the ratio is, the finer the extinction ratio is and the narrower the full-width at half maximum will be.

分析表明器件具有法布里－珀罗腔干涉仪的特点，耦合器的耦合比系数类似于法布里－珀罗腔的反射率，耦合比系数越大，输出光谱半高全宽度越窄，消光比越好。

Since it is difficult to achieve complete orthogonal spread spectrum code sequence, and sometimes impossible to achieve orthogonal in the CDMA system, there were major multiple-access interference, greatly limiting the capacity of the system users.

摘要由于扩频码序列很难实现完全正交，有时甚至是不可能达到正交，在CDMA系统中存在着严重的多址干扰，极大地限制了系统用户容量。

The proposed method first employs covariance matrix tapers to obtain the interference covariance function and its corresponding spatial spectrum in non-ideal scenarios.

该方法首先利用协方差矩阵加权得到非理想情况下的干扰协方差函数和对应的空间谱，然后根据周期延拓后的干扰空间谱估计干扰自由度。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

Based on Wavelet Packet Decomposition, Entropy Threshold Method has been put forward to reject the Discrete Spectrum Interference in on-line PD monitoring.

首次提出用于抑制局部放电在线监测中周期性窄带干扰的小波包变换熵阈值法。

The Gaussian properties of laser beams may cause the appearance of gradients in the interference pattern in the measuring volume and a broadening of Doppler spectrum....

本文定量地论述了高斯光束的各因素对测量精度的影响；给出了测量误差表达式，经过各种情况下的理论计算值的对比和分析，得出了两束腰分别在测量区两侧，等距离时，干涉条纹空间频率梯度引起测量误差最小的结论。

The variance of Gaussian distribution is the sum of the variance of the spread spectrum signal and the variance of the noise, so if it; is estimated, it can be used as the threshold in designing the interference suppression filter.

由于高斯分布的方差即为直扩信号和高斯白噪声方差之和，因此估计出变换域数据的方差，将为频域抑制滤波器的门限设置提供参考。

The Lagrange multiplier was firstly used for solving spectrum optimization problem with the interference factor.

首先，讨论了采用拉格朗日乘子求解带串扰项的频谱优化方法。

On the basis of analysis and comparison of conventional and some modern dielectric loss measurement methods in this paper, considering the difficulty consist in the dielectric loss measurement, such as the problem of the locale measurement of dielectric loss the suffering the interference of the electric field in the electrified wire net, the influence of harmonics and the leakiness of frequency spectrum due to the change of the frequency in power supply etc. a new measurement method which the frequency conversion anti-jamming technology combines the fundamental waves phase detachment method is presented.

论文在分析了传统介质损耗测量方法和现代介质损耗测量方法的基础上，针对介质损耗检测中存在的技术问题，如现场测量时工频电网强电场干扰问题、高次谐波影响问题、供电电源频率改变所引起的频谱泄漏和栅栏效应等问题，提出了采用变频抗干扰技术和基波相位分离法相结合的新型测量方法。

Based studies were done on radiation spectrum, voltage to current character and modulation property of white LEDs when they are used as optical transmitters. Then the configuration and systematic design techniques are concentrated concerning white LED lighting source communication with numerical analyses and computer simulations done as well as high speed modulation techniques, visible light receiver design and means to alleviate inter symbol interference along with background noise problem.

在对白光LED用作通信光源时的光谱特性、伏安特性、调制特性等物理特性做深入分析的基础上，重点研究了白光LED照明光源通信系统的组成结构和系统设计，进行了数学计算分析模拟，并设计出了白光LED高速调制电路和可见光接收电路，并就如何削弱码间串扰和背景光噪声对通信系统的影响进行了讨论分析。

The second is to cut a mere 100 calories from your diet , which is the equivalent of a tablespoon of butter.

第二个就是从你的饮食中减少一百卡路里，只是相当于一大汤匙的黄油。

This is where the Rorschach test comes in.

现在，罗氏测试就出现了。