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对于现有通信方式,超宽带(UWB)脉冲通信技术是一种具有很多优势的新型通信技术,文章主要对超宽带脉冲通信优势、技术实现等方面做出了分析和阐述,并讨论了超宽带脉冲通信未来发展的应用领域。 相似文献
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用于超宽带穿墙雷达的脉冲产生技术是一种无载波极窄脉冲产生技术,在无线电通信领域有着广阔的应用前景.提出了使用延时芯片和ECL门产生极窄脉冲的方法,并对其产生原理做了理论分析.设计了原理框图和电路图,最后给出并分析了试验结果. 相似文献
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用于超宽带穿墙雷达的窄脉冲产生技术 总被引:1,自引:0,他引:1
用于超宽带穿墙雷达的脉冲产生技术是一种无载波极窄脉冲产生技术,在无线电通信领域有着广阔的应用前景。提出了使用延时芯片和ECL门产生极窄脉冲的方法,并对其产生原理做了理论分析。设计了原理框图和电路图,最后给出并分析了试验结果。 相似文献
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超宽带(Ultra Wideband,UWB)通信系统的脉冲宽度很窄(纳秒量级),单个脉冲能量非常小,若单纯在接收端做同步,则很难实现.因此收发两端联合设计,通过数据帧前置导频同步码是比较理想的选择,一方面能辅助系统快速捕获实现同步,另一方面为后续均衡提供训练序列.插入导频序列后会带来一定的功率和效率损失,但从全局来看,是值得的. 相似文献
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脉冲波形对超宽带通信系统性能的影响 总被引:1,自引:0,他引:1
超宽带(UWB)技术的特点是传输持续时间极窄的脉冲,纳秒级窄脉冲(称为monocycle)的选择将直接影响到UWB通信系统的性能。本文研究了一种新的基于小波函数的超宽带窄脉冲,并比较其和传统的超宽带窄脉冲在AWGN信道中采用直接序列扩频(DS)的UWB系统性能。仿真结果表明了基于小波函数脉冲波形的UWB系统性能优于基于传统超宽带窄脉冲的UWB系统。 相似文献
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介绍了超宽带无线通信系统的技术背景和标准的发展状况,重点阐述了几种基于窄脉冲的数字超宽带系统的体系结构,分析了全数字超宽带系统实现过程中的关键技术,包括脉冲成型、高速模数转换和信号检测与接收技术等,并且探讨了相应的解决方案。 相似文献
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There are serious intersymbol interference (ISI) and signal attenuation in wireless ultraviolet communication system.Aiming at this problem,an improved constant modulus fractionally spaced equalizer (CMA-FSE) based on signal-to-noise (SNR) estimation was proposed.The algorithm combined the fractionally spaced equalizer (FSE) and constant modulus algorithm (CMA) for blind equalization of wireless ultraviolet channels.The input SNR was measured by the mean square value of the received signal,and it was used to determine the best iterative step to ensure the convergence of the equalization algorithm.Simulation results show that the improved CMA-FSE algorithm can converge rapidly under various SNR,and it can effectively suppress ISI and improve the BER performance of the system.Compared with the existing algorithms,the improved algorithm is more useful in channel tracking and noise suppression. 相似文献
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A considerable amount of attention has been given in the literature to the use of wavelets for modulation and equalization. In this correspondence, we present an equalization algorithm for a wavelet packet-based modulation scheme. A nonideal channel can be divided into a set of bands, where each band can be approximated as a simple attenuation and delay channel. Wavelet packets, being narrowband and orthonormal, are a natural choice for realizing such bands. Thus, if the data sequence is used to modulate a set of wavelet packets, the equalization problem reduces to that of determining the delay introduced by the channel for each of the wavelet packets (if the wavelet packets do not overlap in the frequency domain) and possibly a change of sign in the decoded symbols. The attenuation affects the SNR at the output of the demodulator, which in turn affects the correct decoding of the transmitted symbols. A minimum square variance algorithm for adaptively choosing the delay has been proposed. The algorithm uses the statistics of the received sequence to pick the appropriate delay. Simulations have been conducted to study the performance of the equalization algorithm and compare it with that of DFT-based DMT scheme 相似文献
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针对传统的自适应均衡算法在稀疏多径信道下性能表现不佳的问题,提出了一种基于基追踪降噪的自适应均衡算法。该算法利用稀疏多径信道下均衡器权值的稀疏性,将自适应均衡器的训练过程看作压缩感知理论中稀疏信号对字典的加权求和,并利用重构算法直接对稀疏权值进行求解,解决了迭代参数设置和收敛慢的问题。采用基追踪降噪作为重构算法并选用变量分离近似稀疏重构对该最优化问题进行求解,既提高了权值的重构精度又降低了计算的复杂度。仿真结果表明,所提算法能够以较低的计算量和较少的训练序列达到更优性能,这对提升系统的通信性能具有参考价值。 相似文献
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机场跑道场景下,由于雾、霾等恶劣天气以及大气散射的作用,使拍摄的图像对比度降低,颜色退化,物体特征难以辨认,影响机场跑道图像的异物检测与识别,带来一些安全隐患。针对上述问题,提出基于双线性插值和中值滤波的改进的引导滤波算法,提高图像对比度和处理速度,利于机场跑道异物检测与识别。仿真结果表明,改进的引导滤波算法与已有算法相比,处理速度提高了2~3倍,且图像彩色值分布更广,直方图更均匀。该算法拥有良好的边缘保持性,在细节增强方面有很好的指导意义。随后将改进的引导滤波算法移植到数字信号处理器( DSP)平台上,以满足实际工程应用对小型化的需求。 相似文献
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A new modulation scheme for IR-UWB communication systems 总被引:1,自引:0,他引:1
Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Bo... 相似文献