查询词典 frequency channel

A detection method of double-threshold constant false alarm movement object on double-base synthetic aperture radar includes finalizing distance compression of various pulse-sampling, dividing orientation time to be multiple CPI, carrying out FFT in each CPI to enter orientation frequency domain, comparing data amplitude of frequency channel at external of clutter region with the first threshold and outputting point trace, making coagulation on point trace, making Hough transform in point trace domain and making decision of the second threshold.

本发明涉及一种用于双基地合成孔径雷达的双门限恒虚警运动目标检测方法，其特征在于：1对每个脉冲采样完成距离压缩；2把方位时间分割成多个相干处理间隔；3在每个CPI内做快速傅立叶变换进入方位频域；4把杂波区外的频率通道的数据幅度和第一门限比较做判决并输出点迹；5点迹凝聚；6在点迹域做Hough变换并做第二门限判决。

A set of complex Morlet wavelet are applied on projection slice of each direction to decompose each projection into several frequency channels,the average and variance extracted are computed in each frequency channel,and then linear regression model is employed to computer realationship feature between frequency channels.1-D DFT is applied to features and the amplitudes of Fourier coefficient are selected as features,then the extracted features are rotation invariant.

该算法是将一定大小的图像进行二维傅里叶变换；其次在变换后的图像中央选择一个圆盘区域，并在方向［0°，180°］内进行等间隔角度频率抽样，实现方向分解，使用一组复Morlet小波对每个方向上的映射切片进行小波变换，从而实现多通道频率分解；在各个频率通道中计算均值和方差作为特征，并利用线性回归模型计算频率通道之间的关系特征；将特征沿方向进行一维傅里叶变换并取其幅值，从而得到旋转不变性特征。

Each data packet is transmitted on a different frequency channel, following a pseudo-random hopping sequence determined by the device address of the master device.

每个数据包经由不同的频率信道传输，并遵循一个由主设备的设备地址决定的伪随机跳频序列。

For orthogonal frequency division multiplexing systems in high-mobility environment, channel variations within one OFDM symbol will introduce intercarrier interference, thus lowering the system performance.

对於应用於高移动通讯环境之正交分频多工(Orthogonal Frequency Division Multiplexing， OFDM)系统，每一个OFDM符元期间的通道时变导致载波间干扰(Inter-carrier Interference， ICI)发生，使得系统效能降低。

Through simulation and computation, some critical values to contral interferences are obtained. These values have directive significance to the design and deployment of WRAN.(4) New methods to measure and analyze spectrum aredevelopedAccording to the shortages of previous spectrum measurements, new methods to measure spectrum occupancy in wide-band and multi-point synchronously is proposed in this dissertation, and the tests last a whole week; the relativities of licensed services are considered when test points are selected. More importantly, data mining and in-depth analysis are carried out with the huge amounts of test data, and a channel analysis method using Channel Vacancy Duration and Service Congestion Rate are proposed. The spectrum relativities of 3-dimension in time, space and frequency are researched also. The correlativity between channel state and history information is discoved, and which will provide the scientific basis to channel modeling, spectrum analysis and decision of CR users.

4提出了频谱测量与分析的新方法针对以前频谱测量工作存在的不足，本文提出了多点同时广域频谱测量方法，测量工作持续了一周的时间，同时考虑了测量地点的选取和频谱授权业务之间的相关性；对测量得到的海量数据进行了数据挖掘和深度分析，提出了使用信道空闲时间(Channel VacancyDuration，CVD)和业务拥塞率(Service Congestion Rate，SCR)进行信道分析的方法，研究了频谱之间的时间、空间、和频率三维立体的相关性，发现了信道状态和历史信息的关联性，为CR用户的信道建模、频谱分析和决策提供了科学的理论依据。

In wireless broadband digital communication, Inter-Symbol Interference caused by time disperse of radio channel is one of main factors that limit bandwidth of communicated information and system performance of communication. In receiver, Orthogonal Frequency Division Multiplexing system can easily cancel ISI and equalize frequency-selective fadings that are both caused by time disperse of radio channel.

在这一系统中，无线信道时延扩展引起的符号间干扰是限制传输性能和信息速率的主要因素之一；而在消除符号间干扰和均衡由无线信道时延扩展引起的频率选择性衰落方面，正交频分复用(Orthogonal Frequency Division Multiplexing，OFDM)技术具有明显优势。

A method for realizing special-line user mechanism at reverse direction in communication system includes confirming end object packet length of reverse special-line user, confirming TxT2Pmin and TxT2Pmax value-taken scope of emission service channel energy to pilot frequency channel power grain TxT2P, setting allowable packet length of data packet being send currently to be not less than confirmed packet length and setting reverse packet as per allowable packet length then transmitting set reverse packet according to set TxT2Pmin and TxT2Pmax.

本发明公开了一种通讯系统中在反向实现专线用户机制的方法，该方法包括：A、确定反向专线用户的终止目标包长；B、确定发射的业务信道能量相对导频信道的功率增益TxT2P的最小值(TxT2Pmin)和最大值(TxT2Pmax)的取值范围；将TxT2Pmin和TxT2Pmax设置在所述取值范围内；C、将当前所发送数据包的允许包长设置为大于等于步骤A所确定的包长，按照所述允许包长组反向包；D、按照所设置的TxT2Pmin、TxT2Pmax发送所组的反向包。

The article introduced the 64 kbit/s serial data transmission channel for relay protection signal,which can overcome the defects of tradition high frequency channel.

模拟试验的必要性传统的高频保护收发信机在电力系统继电保护信号的传输方面起到了很重要的作用。

It is used for inside communications in the power system and for transmitting information about maintenance of transmission line,and may be also used for common public service network,and as high frequency channel,movement signal and communication channel for relay protection in power system.

用于电力系统内部的通信及输电线路维护保养信息的传送，也可用于一般的公共服务网络，作为电力系统继电保护的高频通道、运动信号及通信频道等使用，同时能起到良好导体屏蔽地线的作用。

A software high frequency channel simulation algorithm is presented aiming at the characteristics of HF channel which has unrepeatability, multipath and fading.

针对短波信道不可逆性、多径以及衰落等特点，提出了一种纯软件的短波信道仿真算法。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。