接收端

Thirdly, the maximum-likelihood CFO estimation algorithms based on null-subcarrier are investigated, and it is shown that the maximum-likelihood CFO estimation algorithm based on equispaced null-subcarriers is equivalent to the CFO estimation algorithm utilizing the correlation of repeated training sequences.

提出了两种基于时域相关峰值检测的同步估计改进算法：1）采用一个OFDM符号做为训练序列，在接收端进行差分相关以解决时间度量函数中出现的平台效应。

In order to achieve the detection of amplitude and phase of the optical signal at the same time,a new homodyne coherent detection system was designed,including the scheme of optical align design and the realization of receiver data processing.

陈楚，黄春晖福州大学物理与信息工程学院，福建福州 350002为实现光信号幅度与相位的同时检测，设计了一种新型的零差相干检测系统，包括光路实现方案的设计和接收端数据处理的实现。

For example, IEEE 802.16e supports vehicle speed up to 120 km/hour, and IEEE 802.20 supports vehicle speed up to 250 km/hour. OFDM systems can be used efficiently in time invariant environments with one-tap equalizers. However, subcarriers are no longer orthogonal to each other in time-varying channels, and this causes the intercarrier interference and degrades the system performance.

传统的正交分频多工系统可以有效率地使用在非时变通道中，且仅需简单的等化器，即可修正通道效应，但在移动的环境中，通道随著时间改变，使得接收端的子载波失去正交性，因而导致子载波之间的相互干扰，使得解调变后的效能降低。

The radio channel is time-variant, frequency-selective and noisy, so the received OFDM signals are corrupted by intercarrier interference.

但是由于无线信道的多径性和时变性，造成了接收端 OFDM 符号子载波间的干扰，为了能够准确地解调 OFDM 信号，就必须对接收到的信号进行信道估计。

For example, IEEE 802.16-2005 supports vehicle speed up to 120 km/hour. OFDM systems can be used efficiently in time invariant environments with one-tap equalizers. However, subcarriers are no longer orthogonal to each other in time-varying channels, and this causes the intercarrier interference and degrades the system performance.

传统的正交分频多工系统可以有效率地使用在非时变通道中，且仅需简单的等化器，即可修正通道效应，但在移动的环境中，通道随著时间改变，使得接收端的子载波失去正交性，因而导致子载波之间的相互干扰，使得解调变后的效能降低。

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。

Up to now, the performance analysis of noncoherent space-frequency coding whose receiver does not know the channel state information and the methods to reduce the encoding-decoding complexity have not been solved, and this has constituted a bottleneck of the research of noncoherent space-frequency coding.

非相干空频码具有接收端不需要知道信道信息的特点，而到目前为止，针对非相干空频码的性能分析和如何降低编译码复杂度的问题还没有得到很好的解决，这些问题已成为研究非相干空频码的瓶颈。

To reduce the receiver complexity,a differential space-frequency transmit diversity scheme was developed with a noncoherent detection method based on the frame structure of the time domain synchronous-orthogonal frequency division multiplexing system.

在采用相干检测方法的发射分集方案中，进行信道估计需要付出很高的代价，为了降低接收端的实现复杂度，根据时域同步正交频分复用系统结构的特点，提出了差分空频发射分集及相应的非相干检测方法。

Leadership teams can be scarily ignorant of how badly their wishes have been distorted, and how much unhappiness there is among those on the receiving end.

领导团队可能完全不了解，他们的意图遭到了多么严重的扭曲，而处于接收端的员工又会产生多少不满。

A method by using 8031 single-clip microprocessor to get the syntonical bit information is presented,based on the characteristic of the modulated singal in ascending cosine envelope.

文摘：利用升余弦包络调制信号的特点，即基带信号为升余弦波，接收端可以利用这一包络，从中提取定时信息。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。