查询词典 frequency channel

Inherent inter-symbol and inter-carrier interference elimination ability of orthogonal frequency division multiplexing system attribute to its cyclic prefix. But the case of multipath fading channels whose the channel impulse response length exceeds the duration of cyclic prefix causes intersymbol interference and intercarrier interference, which may degrade system performance severely.

正交频分复用系统中的循环前缀具有一定的抗码间干扰和子载波间干扰的能力，但是当多径衰落信道的最大信道脉冲响应长度超过了循环前缀长度时，OFDM系统的性能将会严重下降。

If the high frequency signal of line protection could not pass through the channel or be normally transmitted, the protection might create failure to operate or maloperation, and it influences the safe and steady operation of the system.

当系统出现故障时，如果线路保护的高频信号不能通过通道正常传送，则有可能出现保护拒动和误动的现象，影响系统安全、稳定的运行。

The algorithm analyzes the system in the frequency domain, then simplifies the finite-impulse-response channel estimate into several memoryless systems.

该算法从频域角度出发，从而将有限冲击响应信道的识别简化为一系列的无记忆系统识别问题。

Differential modulation is also a widely used method to the case of no knowledge of the channels in the receiver. Here we propose noncoherent sequence detection for differential space-frequency modulation, which can be used to alleviate the error floor that occurs in a multipath channel with long time delay expansion.

在接收端不知道信道状态信息的情况下，差分调制也是一种被广泛采用的技术，论文提出了应用于差分空频调制的非相干序列检测方法，该方法通过积累多个符号上的信道信息来完成发送符号的检测，可以消除由于长的信道延迟扩展带来的误码平层。

Multi-channel linear-phase nonuniform filter banks with proper sampling factors are designed which are applied to rows and columns of the input image, respectively, according to its power spectrum distribution. By this procedure, the image can be segmented nonuniformly in the frequency domain.

根据输入图像的频谱能量分布和实际应用的需要，设计具有合适采样因子的线性相位非均匀滤波器组并将其应用于对图像行、列的处理中，实现对整个图像按照频谱能量的高低进行灵活分割的过程。

In the system, we adopt a balance-channel frequency offset structure,phase-locked IF tracking technique and opened-loop precorrection.

在系统结构上采用了平衡通道频率补偿技术、中频锁相跟踪技术和开环预校正技术。

In anFDD wireless system, the duplex spacing between uplink and downlink islarger than the coherence bandwidth of the mobile radio channel, thus theuplink and the downlink small-scale fading is uncorrelated. Moreover, thearray response is correlated with the frequency of the signal carrier. So it isimpossible to resue the uplink weights for downlink beamforming. As aresult, the application of smart antenna for the downlink is a difficult problem.

在频分双工系统中，由于上、下行载波的频率差大于相干频带，上、下行信道衰落是不相关的，而且阵列响应也与信号的载波频率有关，因此，上行信道不能直接用来估计下行信道，故智能天线应用于下行链路是一个难点。

By this model, the target IF return of sum, difference and SLB/SLC antenna channel of the trilobe of frequency-phase scanning 3-D radar could be represented in one uniform expression accurately.

提出了一种三坐标雷达目标中频回波模型及其模拟方法，通过对和、差及辅助通道的目标三联波束回波统一建模，可以全面逼真地模拟频相扫三坐标雷达的目标回波。

The WRAN endpoint can transmit an orthogonal frequency division multiplexed signal comprising 2048 subcarriers in a channel.

WRAN端点可以在信道中传输正交频分复用信号，所述信号包括2048个子载波。

The front and center channel speakers are made with a bamboo diaphragm which provides a tightly intertwined fiber to deliver greater rigidity and accuracy, resulting in clear reproduction of sounds over a wide frequency range, from massive explosions to metallic clangs.

前方和中央声道扬声器均采用竹隔膜提供一个紧密交织纤维以提供更大的刚性和精度，造成清晰的声音再现了一个宽的频率范围，从大爆炸到金属 clangs。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。