窄带

With the present lasers, X-ray microscopy can be made using narrow band emission or black body radiation from laser plasmas.

就目前的泵浦激光条件，采用窄带辐射和黑体辐射可进行水窗波段X光显微成像的实验研究。

The characteristic and quantity of spread spectrum address code has great influence and restriction to CDMA system performance and capability improvement.

目前，数字移动通信系统的两大主流是窄带的TDMA和宽带的CDMA，人们正在对CDMA进行热烈的讨论和进一步的研究。

If the system is narrow band system,the noise is color noise and matching filter cannot be used.

如果系统是窄带系统，噪声为色噪声，无法使用匹配滤波器，不能提高信噪比。

This paper proposed a new method of distance measurement named the continuous wave narrow bandwidth frequency modulation method.

本文提出了一种连续窄带调频的超声波测距方法。

After analyzing the limitation of slow convergence in adaptive Least Mean Square algorithm, it is brought forward the method of transforming signal into frequency domain, taking advantage of the orthogonality of discrete Fourier transform, the adaptive LMS filter is performed for each frequency element in transform domain.

四川大学博士学位论文在频域自适应滤波的基础上，提出了一种权值反馈方法抑制图像传输中的多个大功率平稳强窄带干扰信号，不仅能加快算法的收敛性能，并具有良好的滤波效果。

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。

Longitudinal distribution pattern of metal lateral displacement in the deformation zone is reconstructed to be quartic plus cubic curve.

关于冷轧窄带和宽带的前张应力横向分布的计算结果与实验结果吻合较好，证明了理论模型是实用可靠的。

With the advancement of DWDM (dense wavelength division multiplexing) technologies, key parts of DWDM apparatus have been greatly developed. Fabry-Perot thin film filters, regarded as multiplex/demultiplex components, have been used extensively.

随着光通信DWDM关键器件技术的愈加成熟，作为DWDM中的复用/解复用器件——法-伯(Fabry-Perot)薄膜窄带滤光片得到了很大发展。

Study on an UV transmission quartz depolarizer with narrow bandwidth.

一种紫外窄带宽透射型石英消偏器的研究

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。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。