查询词典 radio-frequency spectrum

By time-varying filtering, we realize the signal selectivity and interference suppression, especially for the signals with time-varying power spectrum. It is shown herein that conventional eigenstructure based methods are lower dimensional special case of the time-frequency subspace fitting method. The closed-form array response estimation algorithms for blind source separation in wireless communication is also developed in the dissertation by exploiting the data structure of second-order statistics of the array output in the presence of multipath. The proposed method achieves array response estimation with little constraint on signal property and propagation environment such as scatters or angular spread. Moreover, the array utilized here can be of arbitrary geometry and even uncalibrated. Since the closed-form solution is obtained, no misconvergency may occur and large amount of computation can be saved. The equivalent feed model and corresponding optimization designation are proposed to realize the downlink multi-user selective transmission. By coherent and non-coherent superposition of the electromagnetical field, multiple beams can be formed using a single array, so that each co-channel user signal is transmitted in each beam and will not interfered with each other. The proposed system scheme implements the digital beamforming and the channel allocation in the base band, therefore is suitable for the utilization of the radio software technology. The feasibility and effectiveness of the proposed model are proved by the RF experiment.

在窄带条件下，GSC－SSF方法还可以提高阵列的虚拟孔径，从而提高估计的性能；可以证明，Cyclic DOA 和SC-SSF方法可看作该方法的特例或近似； 3、提出了二维GSC－SSF方法和宽带谱相关DOA矩阵方法，利用信号的循环平稳特性解决了宽带条件下二维 DOA 估计问题，并具有阵元数少、计算量较小的特点； 4、提出了时频子空间拟合和宽带时频DOA估计算法，将联合时频分析的理论和方法引入到阵列信号的空间谱估计研究中，利用时变滤波实现信号选择性测向和干扰抑制，特别适合于谱时变信号；可以证明传统特征结构法可看作是时频子空间拟合方法的特例； 5、提出了多用户环境下阵列响应的估计方法——CARE方法，该方法对信号结构和传播参数（主要是散射源分布与角度散布）的约束较少，适用于各种几何结构的阵列甚至未校准的阵列，能够直接得到阵列响应的闭式解，因此计算量小、稳健性好，不存在收敛问题； 6、提出了针对多用户下行选择性发送的阵列等效激励模型、优化设计方法及其系统实现方案，通过空间场的相干叠加与非相干叠加使得单一阵列能够形成多个波束，并保证各波束内的用户信号各不相同且相互干扰最小；其系统方案具有在基带实现数字波束成形、信道分配并便于软件无线电实现的特点，其有效性已得到外场实测数据的证实。

This anti-bugging device can trace concealed microphones, closed-circuit televisions, radios, laser-based wall snoopers, hidden cameras, etc. it can also scan a wide-ranging spectrum to detect spying devices from Japan, Germany and the United States which use different radio frequency.

这次反窃听装置，可以追踪隐蔽麦克风，闭路电视，收音机，基于激光的墙窥探者，隐藏的照相机等，也可以扫描一个范围广泛的频谱侦测间谍设备从日本，德国和美国使用不同的无线电频率。

Electromagnetic compatibility and Radio spectrum Matters;ElectroMagnetic Compatibility standard for Very Small Aperture Terminal, Satellite News Gathering, Satellite Interactive Terminals and Satellite User Terminals Earth Stations operated in the frequency rangesbetween 4 GHz and 30 GHz in the Fixed Satellite Service FSS

您当前所在的位置：首页→标准大全→欧洲电信标准→电磁兼容和无线频谱事务甚小孔径终端，在固定卫星业务中运行于 4 GHz和30 GHz频率范围的卫星新闻采集，卫星交互终端和卫星用户中断地面站的电磁兼容标准

Based upon our first paper and continuing the "Standard candle" classification by use of the component linear distance D, we attain to the following statistical correlation of some type of Quasars with largest angular diameter Q_: the correla- tion between visual magnitude and redshift; the correlation between its absolute magnitude, radio-luminosity of single frequency, integral radio Iuminosity, colour in- dex difference Q and D.

本文在第I部分的基础上，继续用类星体射电子源线距D进行"标准烛光"分类，经过统计分析，得到了子源角径最大的一类类星体的一些统计规律：它的视星等与红移之间，它的绝对星等、单频射电光度、积分射电光度和色指数差Q与D之间有很好的相关性等。

Guglielmo Marconi, recognizing the possibility of using these waves for a wireless communication system, gave a demonstration (1895) of the wireless telegraph, using Hertz's spark coil as a transmitter and Edouard Branly's coherer (a radio detector in which the conductance between two conductors is improved by the passage of a high-frequency current) as the first radio receiver.

Guglielmo Marconi，认可使用这些波浪的可能性为一个无线通信系统，给了一次示范(1895)无线通信机，使用赫兹的火花卷因为发射机和Edouard Branly 的coherer (导率在二个指挥之间被高频率潮流段落改进)的一台无线电探测器如同第一无线电接收机。

This is the government hopes to radio management departments of radio frequency distribution system reform.

本文希望以此为政府无线电管理部门对无线电频率分配体系的变革提供参考。

Think about when the car is parked inside your garage attached to your house; and the remote starter is interfered by other radio frequency and accidently turned on.(Your naughty kid may do this. Or, some crooks try to open your garage door by emitting random radio signals; always lock the man door). The car will keep pumping carbon monoxide gas into the garage, and the poisonous gas will seep through any cracks or holes to get into the house. Your whole family may get kill because of this (sleeping through the night and never get up).

试想一下如果那辆汽车停在你的车库内，车库又是和房屋连在一起的那种，万一遥控启动装置被其他无线电频道干扰而意外启动（你家里顽皮的孩子可能会这样做的，又或者一些小偷也会故意发射一些随机的无线电信号来尝试打开你的车库门，因此门一定要锁好），汽车就会不断地在车库里面释放一氧化碳，而这些有毒的气体又会透过门缝或者孔洞钻进屋内，严重时甚至可以置全家人于死地。

And the channel composed of the new radio induction system for communication is different from the parameter-constant channel and the traditional parameter-changing channel, its parameter is decided by the mutual induction between its antenna and induction-cable, by the location of its antenna, by the signal frequency passing through, its parameter has nothing to do with the time parameter. The channel composed of the new radio induction system is a new parameter-changing channel independently of time for communication.

而且，由新型无线感应系统组成的信道既不是恒参信道，也不是一般目前所知的变参信道，其信道传递函数的幅值只与信号的频率有关，与系统中天线和感应电缆之间的互感和天线的位置有关，而与时间无关，其信道传递函数的相位只与天线的位置有关，而与时间无关，由新型无线感应系统组成的信道是一种不随时间变化的新型变参信道。

So it holds a ideal ability to anti-interference and has 2 scalar level resolution in location and measuring velocity than traditional radio induction technology. And the channel composed of the new radio induction system for communication is different from the parameter-constant channel and the traditional parameter-changing channel, its parameter is decided by the mutual induction between its antenna and induction-cable, by the location of its antenna, by the signal frequency passing through, its parameter has nothing to do with the time parameter.

而且，由新型无线感应系统组成的信道既不是恒参信道，也不是一般目前所知的变参信道，其信道传递函数的幅值只与信号的频率有关，与系统中天线和感应电缆之间的互感和天线的位置有关，而与时间无关，其信道传递函数的相位只与天线的位置有关，而与时间无关，由新型无线感应系统组成的信道是一种不随时间变化的新型变参信道。

The most efficient and most common circuit for radio-frequency selection and amplification used in radio receivers is the superheterodyne.

最高效率和多数最共同的电路为radio-frequency 选择和放大作用被使用在无线电接收机是超外差收音机。

We got alerted a couple of times while we were down south that HETs were on the way to bring us back up north because things were going to go hot again, but it was just rumors.

南下的途中我们不只一次得到警告说重型装备运输车将拉着我们重新北上，因为局势正在变得重新紧张起来，但这只是谣传。

It's the one where they find the ghost in the salt mine.

这一集是演他们在盐矿找到鬼