查询词典 SNR

When the launched SNR is more than the threshold, the cognitive network is an inter-user interference limited system, the base station selects the stochastic wave forming mode of a single beam and selects the user which has the maximum received SNR from the sub-scribers as a current communication object; when the launched SNR is less than the threshold, the sub-scriber network is a noise interference limited system. The base station selects the opportunistic SDMA of multi-beams and then selects a plurality of scribers with the maximum received SNR from the sub-scribers as the communication objects, thus realizing the maximization of system capacity.

当发射信噪比大于门限值时，认知网络为用户间干扰受限系统，基站选择单波束的随机波束成型模式，在从用户中选择接收信噪比最大的用户作为本次的通信的对象；当发射信噪比小于门限时，从用户网络为噪声干扰受限系统，基站选择多波束的机会式空分多址模式，在从用户中选择信噪比最大的几个用户作为通信对象，从而实现了系统容量最大化。

The main contributions in this area are summarized as follows,? The closed-form formula and its asymptotic form of system outageprobability are derived, through which it is shown that the outage probability decreased by a factor ofγ~(hereγdenotes the average SNR);? The closed-form formula of outage capacity is derived, through which weshow that 1 outage capacity increases with the increases of mean value of sytem SNR, and decreases with the increase of the variance of system average SNR; 2 in order to obtain higher outage capacity, the number of transmit antenna should be no more than that of receive antennas.?

特别的，针对多用户发送天线选择／最大比合并系统，主要贡献总结如下：·理论推导出中断概率的闭式解及其近似解，通过该近似解，可以得到中断概率以γ~的形式减少(这里γ是平均信噪比SNR)·推导出平均中断容量的闭式表达式，研究表明：1中断容量随着有效平均SNR的均值的增加而增加，随着有效平均SNR的方差的增大而减小；2为了获得更高的中断容量，发送天线的数目应当不大于接收天线的数目。

The findings: with the apparent dominant frequency of the Ricker wavelet rising, the detection SNR will get worse gradually, it is obvious that the variety of the SNR is slower during the portion of high frequency than during the portion of low frequency; in the usual range of seismic prospecting frequency, the SNR of the chaotic oscillator detection system could partially make up the amplitude attenuation aroused by the transmit of the seismic wave; the results could provide help for detecting the event constituted by aberrant wavelets.

本文以Ricker子波模拟地震子波，研究Ricker子波视主频变化的相应检测效果。研究结果：随着Ricker子波视主频的升高，检测SNR逐渐变差，在高频部分SNR的变化明显比低频部分缓慢；在通常地震勘探频率范围内，混沌振子系统检测SNR有可能部分补偿由于地震波传播引起的幅度降低；为检测由畸变子波构成的同相轴提供一定的可能。

Simulation results shown for QPSK and 8-PSK, demonstrate that the new estimator clearly performs as well as the best SNR estimator in each SNR range.

仿真结果表明，这种新的估计算法在更大的信噪比范围内的表现要优于其他现存的估计算法。

To solv e this problem, a circular correlation method based on FFT for C/A code acquisition was discussed. To improve SNR in weak signal environments, this text put forward a modified acquisition by circular correlation. The analysis and simu lations indicate that the method can make the perˉ formance of acquisition in low SNR improved and verify its validit y.

针对弱信号环境下低信噪比的情况，研究了适合该算法的解决方案，并提出改进的捕获算法，理论分析与实验结果证实了该方法在弱信号环境下具有较好的捕获性能，并能大幅度减少捕获时间。

Aimed at low-SNR infrared images,the principle,invariant property and computational methods of Pseudo-Zernike moments are analyzed,and a method for low-SNR infrared target detection based on Pseudo-Zernike moments is proposed.

针对低信噪比红外目标图像，分析了伪Zernike矩的基本原理、不变性和计算方法，提出了低信噪比红外目标检测的伪Zernike矩方法，并比较了模板匹配、Hu矩、伪Zernike矩方法的目标检测效果。

On the basis of the above, the bearing estimation property of vector sensor is discussed, including the probability density function and mathematical characteristic of bearing estimation, the influence of electrical rotation, bearing correction in the low SNR, the estimation method of SNR, the restriction of multiple targets bearing estimation, the postposition process and so on.

在此基础上，继续讨论单矢量传感器的方位估计性能问题，包括方位估计的概率密度函数及其数字特征、仿真、电子旋转产生的影响、低信噪比的方位纠偏、信噪比估计方法、多目标方位估计的局限、后置处理等内容。

Aimed at low-SNR infrared images, this paper analyzed principle and computational method of Zernike moments, proved rotation invariant property, proposed a method for low-SNR infrared target detection based on Zernike moments,and compared target recognition effect among template matching, Hu moments and Zernike moments via experiment.

由于低信噪比红外图像本身所具有的目标特征很不明显、背景特征比较强等特点，模板匹配识别方法、Hu不变矩等并不适用于低信噪比红外目标检测。

Two suboptimum alternatives are presented in the low or high SNR channel to reduce the energy consumption. Under the identical local sensor and the same channel SNR assumption, we study the fusion statistic in the last.5 Based on modified Apriori algorithm, this thesis proposes a novel node association rule mining algorithm for exploiting the inherent correlations between sensor readings.

考虑到传感器网络的资源受限，对信噪比较高或较低的情况下又提出了两种简化的次优融合规则，最后讨论了同类传感器模型下的融合情况。5通过对传统Apriori算法的改进，提出了一种节点关联规则挖掘方法来发现大量节点之间的有趣关联或相关联系，以此消除节点之间的信息冗余。

And images processed with the incorrect parameters will be worsened. This paper analyses the effect of SNR on autofocus and proposes an adaptive filter in SAR azimuth subsampling to keep SNR as high as possible, so that the performance of autofocus can be improved and higher image quality achieved.

该文分析了信噪比对自聚焦的影响，提出利用自适应滤波器来做方位向预滤波和降采样，在降低采样率的同时，保持原始图像的信噪比，再经有效的自动聚焦算法，得到较准确的多普勒参数估计值，从而获取高分辨率SAR图像。

Apllied the data of QuickBird-2——the highest resolution remote sensing,and based on the theory and methodology of fractal geometry,we have quantitatively studied remote sensing lineations in Gaolong gold deposit of Guangxi.

采用Quick Brid-2高分辨率卫星遥感数据，通过分形几何学的盒计维数法，定量研究广西高龙金矿区遥感线性构造。

So, sometimes, to change the color can not be your food (referring to the above-mentioned crustacean) has been a sign of boiling over.

所以，有时，来改变颜色，不能你的食物一直是沸腾了的迹象。