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信号调制与解调技术是光纤通信系统不可或缺的部分,直接影响通信信号传输的速度、可靠性和效率。在高速光纤通信系统中,信号调制与解调面临诸多挑战,如噪声干扰、信号失真和数据处理的复杂性等。对此,阐述信号调制与解调的基本原理,详细分析高速光纤通信系统中信号调制与解调的优劣,深入探讨信号调制与解调技术的应用,以更好地优化高速光纤通信系统的性能。 相似文献
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介绍了通信侦察系统的组成和功能,讨论了通信系统中天线、射频前端、接收机及信号处理终端等的设计方法和设计技术,分析了通信信号侦察中信号的快速搜索、截获、调制识别和高精度测向、定位等关键技术. 相似文献
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一种小型通信系统的设计 总被引:1,自引:0,他引:1
介绍了一种小型通信系统的设计方法及其工作原理。系统中的发射机单元采用调频方式实现音频信号的调制而接收机单元对调频信号进行解调,恢复出原始的音频信号。 相似文献
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为解决紫外光通信过程中产生的随机散射,造成的紫外光通信性能降低等问题,提出基于人工智能技术的紫外光通信调制方法。该方法详细分析紫外光通信特性,确定通信过程中发生衰减的通信信号,并计算损耗结果;采用正交频分复用OFDM技术映射该信号,形成紫外光通信OFDM信号,并采用离散傅里叶逆变换和离散傅里叶变换优化OFDM技术,获取最终的紫外光通信调制信号;将该信号作为卷积神经网络的输入,通过网络的学习和训练输出通信识别调制结果。测试结果显示:该方法可确定发生损耗的通信信号,调制信号的获取性能较好,信息结果均在0.94以上;不同调制阶数下,接收码元串的误码率均在2%以下,调制效果良好,平均发射功率均在0.94以上。 相似文献
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无线电通信技术的不断发展,使得通信环境日渐复杂多变。通信信号可以采用多种多样十分复杂的调制方式,而怎样有效快捷地监控和识别这些通信信号就显得至关重要,而通信信号调制识别的基本任务是在有多信号的环境和有噪声的干扰之下将接收信号的调制方式和其他信号参数确定出来,从而进一步对信号进行更深程度地分析和处理。 相似文献
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针对传统卫星重叠通信中单个掩护信号带宽以及功率容限不够的问题,利用卫星转发器频谱环境中多个掩护信号提出了一种频域分割-子谱功率控制联合优化的多掩护信号重叠通信方法,建立了隐蔽通信信号传输性能和隐蔽性能的双目标优化问题,信关站侧采用感知的历史频谱数据训练生成支持向量机回归预测模型,用来预测不同转发器频谱环境下隐蔽信号的通信性能和隐蔽性能,并将训练好的预测模型下载到通信终端;终端侧利用双目标背包算法将支持向量机回归预测模型预测的隐蔽信号的通信性能和隐蔽性能作为价值因素、掩护信号个数作为背包重量来选择转发器频谱环境中的掩护信号,并且求解出隐蔽信号的频域分割和子频谱的功率控制参数,从而实现终端通信信号隐藏在卫星转发器的频谱环境中的目的。 相似文献
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主要阐述了盲源分离技术应用于无线通信系统时面临的若干问题和解决方案的研究现状。在无线通信系统中,参与混合的源信号是射频通信信号和干扰,这些源信号往往具有循环平稳特性;完成源的混合的无线信道往往受环境影响而发生变化,即具有时变特性;受客观实际条件的限制,观测信号数目往往少于混合源的数目,即表现为欠定混合特性。因此,将盲源分离理论应用于无线通信系统中时,需要特别关注的是循环平稳源、时变、欠定等条件下的盲分离问题。 相似文献
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Raja Syamsul Azmir Raja Abdullah Asem Ahmad Salah Alyani Ismail Fazirulhisyam Hashim Nur Emileen Abdul Rashid Noor Hafizah Abdul Aziz 《ETRI Journal》2016,38(2):302-313
Use of a passive bistatic radar (PBR) system in the surveillance or monitoring of an area has its advantages. For example, a PBR system is able to utilize any available signal of opportunity (for example, broadcasting, communication, or radio navigation signals) for the purposes of surveillance. With this in mind, there are potentially many research areas to be explored; in particular, the capability of signals from existing and future communication systems, such as 4G and 5G. Long‐Term Evolution (LTE) is the world's most current communication system. Given this fact, this paper presents the latest feasibility studies and experimental results from using LTE signals in PBR applications. Details are provided about aspects such as signal characteristics, experimental configurations, and SNR studies. Six experimental scenarios are carried out to investigate the detection performance of our proposed system on ground‐moving targets. The ability to detect is demonstrated through use of the cross‐ambiguity function. The detection results suggest that LTE signals are suitable as a source signal for PBR. 相似文献
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单信道多个时频重叠的混合通信信号盲分离具有广泛的应用价值,是近年来通信信号处理研究领域的一个热点和难点,而单信道多个混叠通信信号的调制识别和信号个数的估计是实现单信道多个混叠通信信号盲分离的基础。该文通过分析数字调制信号的二阶和四阶循环累积量的循环频率特性和结构特征,提出一种基于循环频率特征的单信道混合通信信号调制识别的方法和实现算法,其主要特点是不需要已知混合信号的个数、功率、载频、符号率及定时等先验信息,对一些典型的数字调制信号(如BPSK, QPSK, OQPSK, MSK等)的随机混合,能够有效地辨识接收信号中所包含的信号个数以及每个调制信号的调制方式。利用计算机仿真实验,考察了不同条件下算法的性能,表明了其可行性和有效性。 相似文献
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A wide-band optical communication system that modulates the envelope of the carrier of a high-speed optical pulse having no relation to the PCM signals, was developed. This optical pulse is supplied from a He-Ne gas laser oscillator that is controlled to generate a single transversal mode. The transmission bit rate of this optical communication system is 123 Mbits/s, and this system has a transmission capacity of three monochrome video signals, three program signals, and one channel of 48-kHz high-speed facsimile signal or one National Television System Commission (NTSC) color TV signal and one program signal. When this optical communication system is used to propagate through the atmosphere for a distance of 2-3 km, reliability is expected to be 99 percent. 相似文献
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Van Phu Tuan 《International Journal of Electronics》2018,105(2):262-273
This article studies a secure communication of a simultaneous wireless information and power transfer system in which an energy-constrained untrusted relay, which harvests energy from the wireless signals, helps the communication between the source and destination and is able to decode the source’s confidential signal. Additionally, the source’s confidential signal is also overheard by a passive eavesdropper. To create positive secrecy capacity, a destination-assisted jamming signal that is completely cancelled at the destination is adopted. Moreover, the jamming signal is also exploited as an additional energy source. To evaluate the secrecy performance, analytical expressions for the secrecy outage probability (SOP) and the average secrecy capacity are derived. Moreover, a high-power approximation for the SOP is presented. The accuracy of the analytical results is verified by Monte Carlo simulations. Numerical results provide valuable insights into the effect of various system parameters, such as the energy-harvesting efficiency, secrecy rate threshold, power-splitting ratio, transmit powers, and locations of the relay and eavesdropper, on the secrecy performance. 相似文献
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无线中继是一种接收其他站点无线信号,并根据接收到的信号生成自身发射信号的装置,下一代移动通信系统中会大量运用一种decode-forward模式的无线中继.这种中继本身有相对简单的协议栈,对接收信号进行解调和基带处理,然后生成发射信号.根据中继协议栈的完备程度,这种中继可以完成差错控制、功率调整、信道测量、干扰协调,甚至有调度功能.本文主要介绍无线中继对移动通信系统的影响、应用场景、相关技术,标准化组织和研究组织对其研究的进展. 相似文献