共查询到19条相似文献,搜索用时 953 毫秒
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介绍了一种可用于超宽带(UWB)穿墙雷达的脉冲发生电路,讨论并分析了UWB中几种常用窄脉冲产生方法的特点及其局限性。基于雪崩三极管和射频双极性晶体管的雪崩特性,设计并制作了UWB脉冲电路发生器,指出电路中需要注意的事项及改进脉冲性能的方法,并获得亚纳秒级的超短、快速前沿的单极性UWB脉冲,幅度为28 V,宽度为0.95 ns。 相似文献
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一种用于UWB通信的正弦调制高斯脉冲 总被引:4,自引:2,他引:2
介绍了FCF对UWB通信的频谱限制,针对目前用于UWB通信的高斯微分脉冲存在带宽过大的问题,提出一种符合频谱限制的正弦调制高斯脉冲波形,并对其在AWGN信道中的误码率性能进行了分析。主要描述了对UWB单周期脉冲特性分析(包括高斯微分脉冲频谱分析、正选调制高斯脉冲频谱分析)和AWGN信道误码率性能分析(包括信道描述、信号特性及误码率分析) 相似文献
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利用光反馈半导体激光器产生超宽带混沌脉冲信号 总被引:5,自引:4,他引:1
提出了一种基于光反馈半导体激光器的混沌特性产生超宽带(UWB)信号的新方法。一个商用的通信波段半导体激光器在外腔光反馈下实现混沌振荡,输出连续波混沌激光,经由一个电吸收调制器后,被调制为一系列混沌脉冲信号。该混沌脉冲信号的频谱特性可通过调节半导体激光器的偏置电流和反馈强度进行控制。实验分别获得了中心频率为4.0 GHz、相对带宽为181%和214%的混沌脉冲UWB信号。进一步数值仿真了偏置电流和反馈系数对混沌脉冲UWB信号频谱特性的影响,实验结果与模拟验证相符。该方法实验装置简单,UWB信号频谱特性易控,可用作未来UWB光纤无线通信系统的光生微波信号发生装置。 相似文献
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文章介绍了UWB脉冲设计所遵循的要求,分析了传统UWB脉冲的波形特征,指出了其不足,并对结果进行了仿真.然后介绍了一种新的PSWF脉冲波形设计方法,并分析了其不仅满足FCC对UWB脉冲的规定,而且克服了高斯脉冲波形不满足正交性的缺点. 相似文献
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基于时域分析理论,研究了UWB脉冲信号经不同反射面反射后信号场强的变化特性。在给出时域反射信号场强计算的解析表达式的基础上,研究了相应的数值逼进计算方法,并仿真分析了垂直和水平极化入射的UWB脉冲信号时域反射信号场强特性。 相似文献
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超宽带是一种与传统无线通信技术有所区别的通信,针对影响超宽带脉位调制技术的因素进行了研究,简要介绍了超宽带的技术特征、调制解调原理和技术优点,重点分析了无载波的TH-PPM信号调制与解调的原理,最后通过理论研究,结合脉位调制的matlab仿真实验,得出跳时码周期对脉位调制的影响。 相似文献
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On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS 总被引:14,自引:0,他引:14
Hamalainen M. Hovinen V. Tesi R. Iinatti J.H.J. Latva-aho M. 《Selected Areas in Communications, IEEE Journal on》2002,20(9):1712-1721
This paper evaluates the level of interference caused by different ultra-wideband (UWB) signals to other various radio systems, as well as the performance degradation of UWB systems in the presence of narrowband interference and pulsed jamming. The in-band interference caused by a selection of UWB signals is calculated at GSM900, UMTS/wideband code-division multiple-access (WCDMA), and Global Position System (GPS) frequency bands as a function of the UWB pulsewidth. Several short-pulse waveforms, based on the Gaussian pulse, can be used to generate UWB transmission. The two UWB system concepts studied here are time hopping and direct sequence spread spectrum. Baseband binary pulse amplitude modulation is used as the data modulation scheme. Proper selection of pulse waveform and pulsewidth allows one to avoid some rejected frequency bands up to a certain limit. However, the pulse shape is also intertwined with the data rate demands. If short-pulses are used in UWB communication the high-pass filtered waveforms are preferred according to the results. The use of long pulses, however, favors the generic Gaussian waveform instead. An UWB system suffers most from narrowband systems if the narrowband interference and the nominal center frequency of the UWB signal overlap. This is proved by bit-error rate simulations in an additive white Gaussian noise (AWGN) channel with interference at global system for mobile communication (GSM) and UMTS/WCDMA frequencies. 相似文献
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UWB(超宽带)技术是继CDMA技术之后迅速发展的一种宽带传输技术,将经过信息调制的基带脉冲进行直接发送,脉冲宽度一般为ns级,因此它的信号能量分布在从DC到几GHz范围。它相对常规窄带传输方式而言有低功率谱、低截获、抗干扰能力强、可高速数据传输、多径分辨能力强和共享频谱等优点。主要介绍了UWB的几种调制技术,包括:TH-PPM、DS-UWB、TH-PAM和TH-OOK。分别阐述了它们的信号调制与解调,并分析比较了它们的性能,得出TH-PPM功率效率最高,是一种最优方案,最后以一种简明方式分析了UWB的应用和未来发展前景。 相似文献
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超宽带脉冲信号的光学生成方法研究 总被引:1,自引:0,他引:1
近年来超宽带(UWB)通信技术迅猛发展,在测量、雷达技术、民用和军事无线通信中有着重要的应用,UWB-over-fiber技术已经成为目前研究的热点,其中就包括UWB脉冲信号的产生方法。区别于传统的电子学方法,光子学产生方法不受电子瓶颈制约,可以实现很高的带宽,并且具有抗电磁干扰、重量轻、结构紧凑的优点。通过对比国内外本领域研究成果,讨论及总结了以下三种原理的UWB脉冲信号的光学生成方法:1)相位调制-强度调制转换(PM-IM);2)半导体光放大器(SOA)的非线性效应;3)频谱塑形和色散所致频域-时域映射,然后对各种方案进行了对比分析。 相似文献
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《Microwave Theory and Techniques》2006,54(10):3681-3687
A novel low-cost low-power fully integrated tunable transmit module composed of a tunable CMOS monocycle pulse generator and compact uniplanar antenna was designed, built, and tested for ultra-wideband (UWB) impulse systems. The CMOS tunable pulse generator integrates a tuning delay circuit, square-wave generator, impulse-forming circuit, and pulse-shaping circuit in a single chip using a standard low-cost 0.25-$muhbox m$ CMOS process. It can generate a monocycle pulse and Gaussian-type impulse (without the pulse-shaping circuitry) signals with tunable pulse duration. A compact uniplanar UWB antenna was also developed and integrated directly with the CMOS pulse generator chip to form the complete integrated tunable UWB transmit module. Measured results show that the CMOS tunable pulse generator can produce a 0.3–0.6-V peak-to-peak monocycle pulse with 140–350-ps tunable pulse duration and a 0.5–1.3-V peak-to-peak impulse signal with 100–300-ps tunable pulse-duration, and the uniplanar antenna has less than a 18-dB return loss and is suitable for transmitting/receiving UWB time-domain impulse signals covering the entire UWB bandwidth of 3.1–10.6 GHz. Good agreement between measured and calculated performance is also achieved. The UWB transmit module was experimentally characterized and its performance is verified. This UWB module finds applications in various time-domain UWB systems including wireless communications and radar. 相似文献
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一种超宽带脉冲发生器的设计与仿真 总被引:2,自引:0,他引:2
利用双极型晶体管的雪崩特性设计了双管并联的超宽带(Ultra-Wideband,UWB)脉冲发生器,通过添加电感使电路的等效负载增加,在维持脉冲宽度基本不变的情况下使输出脉冲的幅度增加到原来的2.5倍。对电路中各元件参数的选取进行详细的分析说明,给出了参数值与脉冲各项性能的关系。仿真得到的UWB脉冲信号幅度为-38.299V,脉冲宽度约为663.265ps,上升时间459.184ps,下降时间约为969.388ps。 相似文献