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asd
航空航天通信技术一般采用模拟通信的频率调制和数字通信的移相键控调制方法。这有利于充分应用信道带宽和能源。频率调制是在一定程度上改变载波或副载波的频率来传输信息的调制方法。移相键控调制是利用载波或副载波的相位跳变来传输信息的调制方法。移相键控又分二相移相键控、四相移相键控和多相移相键控,其中以四相移相键控和八相移相键控调制方法的效率较高(Aerospace communications technology commonly used analog communication of frequency modulation and the digital communication phase shift keying modulation method. This is helpful for making full use of channel bandwidth and energy. Frequency modulation is changed to some extent carrier or subcarrier frequency to transmit information modulation method. Phase shift keying modulation is the use of carrier or subcarrier phase jump to transmit information modulation method. Phase shift keying and binary phase shift keying, four phase shift keying and multiple phase shift keying, of which four phase shift keying and eight phase shift keying modulation method of high efficiency
)
- 2011-07-13 11:21:08下载
- 积分:1
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fast-subspace-algorithm
为了对空间辐射源进行精确定位" 建立了基于任意阵列对多目标源进行二维DOA估计的数学模型。将 MUSIC算法推广到三维空间阵列可以对辐射源进行二维高精度测向,但由于其需要估计接收数据的协方差矩阵和进行特征分解, 因而其计算量较大。利用多级维纳滤波器的前向递推获得信号子空间和噪声子空间,不需要估计协方差矩阵和对其进行特征分解,从而降低了MUSIC算法的计算量。将文中的方法应用于任意阵列的二维DOA估计中进行计算机仿真和实际侧向系统性能验证,实验结果均表明该方法达到了MUSIC算法的性能,但与常规MUSIC算法相比降低了计算量.( In order to space radiation source for precise positioning" based on arbitrary array to multiple target source 2D DOA estimation model. The MUSIC algorithm is extended to three-dimensional space to two-dimensional array of radiation source for high precision direction finding, but due to the need to estimate the covariance matrix and eigenvalue decomposition, and the large amount of calculation. Use of multistage Wiener filter forward recursion received signal and noise subspace, does not need to estimate the covariance matrix and the eigenvalue decomposition, which reduces the computation of MUSIC algorithm. This method is applied to an arbitrary array DOA estimation for computer simulation and actual lateral system performance verification, the experimental results show that this method achieves the performance of MUSIC algorithm, but with the conventional MUSIC algorithm reduces the calculation amount.)
- 2012-03-09 16:03:44下载
- 积分:1
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TQ2440
本文系统的介绍了TQ2440开发板相关知识,对这方面的读者很有作用。(This article describes the system development board TQ2440 knowledge, useful in this respect the role of the reader.)
- 2010-01-29 19:52:52下载
- 积分:1
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3G
说明: 3G方面的论文,TD-CDMA WCDMA(Papers on 3G, TD-CDMA WCDMA)
- 2011-05-05 10:55:12下载
- 积分:1
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uCOSonTMS320F281x
uC OS_II在DSP芯片TMS320F281x上的移植(OS_II embedded DSP chip in the transplant TMS320F281x)
- 2007-03-12 17:24:53下载
- 积分:1
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Stability-of-Time-Delay-Systems__Control_Engineer
a reference book about stability of time delay systems
- 2012-04-17 21:26:38下载
- 积分:1
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MIMO-OFDM_Systems
说明: In order to solve the problem of low bandwidth
utilization while the peak-to-average power ratio(PAPR) is
reduced.
- 2020-01-24 20:59:56下载
- 积分:1
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Principles-Of-Communication
通信系统仿真原理与无线应用 《通信系统仿真原理与无线应用》系统地介绍通信系统的设计、分析和仿真方法,还提供了大量极具参考价值的仿真实例。(Simulation principles of communication systems and wireless applications. "A systematic introduction to the design, analysis and simulation of communication systems, it also provides a large number of simulation examples of great reference value.)
- 2012-04-16 09:58:48下载
- 积分:1
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4
说明: :载波频率偏移是OFDM系统实现的关键问题之一。分析了OFDM 系统载频偏移估计的2
种算法,即利用循环前缀和训练序列方法。它们均为最大似然估计方法。分别讨论了它们的基本
思想、实现方法和仿真结果。可以看出基于循环前缀算法复杂度较小,精度不高,而基于训练序列
的算法有较高的估计精度,但降纸了系统传输效率。(Abstract:Carrier frequency ofset is one of the key problems in OFDM system.Two foundational methods
。cycling prefix—based and training sequence—based algorithms。to estimate OFDM carriers~equency
ofset are analyzed.Then it discusses their basic thoughts。implementing methods and simulation resuits.
Finally。merits and demerits of every algorithm are supposed.It concludes that the cycling prefix—
based algorithm has less complexity and less precision。and that the training sequence—based algorithm
has better estimation performance at the cost of transmission efficiency.)
- 2010-05-18 18:34:44下载
- 积分:1
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§3移动信道中的传播与分集接收
说明: 移动通信基础,经典介绍了移动通信最新技术及前沿动态。经典再现(Mobile Communication Foundation)
- 2020-06-17 21:40:02下载
- 积分:1