查询词典 antennas

This paper analyzes the application of MC-CDMA in a multiple antennas environment and derives an equation for the closed-form asymptotic spectral efficiency of the system with matched filter and linear minimum mean square error front-ends.

该文从信息论的角度分析了MC-CDMA在多天线通信系统中的应用，得到了当采用匹配滤波器检测子和线性最小均方误差检测子的渐进频谱效率的闭式表达，研究了可用于指导系统设计的频谱效率与发送天线数和接收天线数的关系。

Under the assumption that the channel state information was available only at the receiver,the capacity of MIMO systems in Rayleigh fading channel was investigated on the basis of information theory. Three special expressions for the MIMO capacity over ergodic flat fading channel were derived.An asymptotic formula for MIMO systems with equal number of transmit and receive antennas in small SNR was also given. Simulation results show that this approximation is relatively accurate.

以信息论的观点为基础，在假设信道状态信息仅收端已知的情况下，采用等功率发射方案，研究了瑞利衰落信道下MIMO系统各态历经信道容量，推导了三种特殊MIMO信道的各态历经信道容量表达式，以及在小信噪比下等收发天线MIMO系统的容量近似公式，并通过仿真进行了验证，仿真结果表明该近似公式比较精确。

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。

Because the rank of the augmented channel matrix is always equal to the number of transmitting antennas, the algorithm can work well in an ill-conditioned channel.

由于扩展信道矩阵的秩等于发射天线数，该算法对信道缺秩的情况不敏感。

The desired signal in the auxiliary antennas may cause angle measurement error by using adaptive sidelobe cancellation in tracking radar. If not effectively encountered, it prevents successful radar target tracking.

跟踪雷达应用自适应旁瓣对消时辅助天线中的期望信号会引起测角误差，若不采取应对措施，雷达无法对目标进行有效跟踪。

The antennas for the radar systems are found in the rotodome that is carried atop the AWACS.

天线的雷达系统发现，在rotodome即通过头顶上的预警。

The Sensor board includes two PCB 2.4 GHz antennas, CR2032 Lithium battery holder and the three pushbuttons.

传感器板包括两个PCB 2.4GHz天线，CR2032锂离子电池座和三个按钮。

The features held by PAA are fast scanning and beam deflection, which are not provided with other traditional antennas.

相控阵天线有常规阵列天线所不具备的特点：快速、无惯性的扫描能力，快速波束赋形能力等。

XAF-derived Navy programs moved on to 200 MHz air search prototypes with 330 KW pulse outputs, very sensitive receivers and planar "bedspring" antennas.

从XAF后，海军计划研制转移到输出功率330KW，工作频率200MHz，具有灵敏的接收机和"弹簧床"天线的对空搜索雷达上。

XAF-derived Navy programs moved on to 200 MHz air search prototypes with 330 KW pulse outputs, very sensitive receivers andplanar "bedspring" antennas.

从XAF后，海军计划研制转移到输出功率330KW，工作频率200MHz，具有灵敏的接收机和"弹簧床"天线的对空搜索雷达上。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐