共查询到20条相似文献,搜索用时 31 毫秒
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Radio astronomy receivers 总被引:3,自引:0,他引:3
A general survey of the principles of radio astronomy receivers is presented. System noise temperature, the sensitivity of different receiver types, and the calibration of receivers are studied. A total-power receiver is analyzed as a basic radio telescope receiver and the results are used to obtain the performance of other receiver types such as the Dicke receiver, Graham's receiver, correlation receiver, and phase-switching receiver. 相似文献
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P-order metric UWB receiver structures with superior performance 总被引:1,自引:0,他引:1
The generalized Gaussian probability density function is shown to better approximate the probability density function of the multiple access interference in ultra-wide bandwidth systems than the Gaussian approximation and the Laplacian density approximation. Two ultra-wide bandwidth receiver structures based on this new approximation using a p-order metric receiver decision statistic are investigated for the detection of time-hopping ultra-wide bandwidth wireless signals in multiple access interference channels. The first receiver outperforms both the conventional matched filter ultra-wide bandwidth receiver and the soft-limiting ultra-wide bandwidth receiver when only multiple access interference is present in UWB channels. The second new receiver with adaptive limiting threshold outperforms the conventional matched filter ultra-wide bandwidth receiver, the soft-limiting ultra-wide bandwidth receiver, and the adaptive threshold soft limiting ultra-wide bandwidth receiver in all multiple access interference-plus-noise environments. In multipath channels, a new Rake receiver based on the p-order metric receiver is proposed for signal detection. Mathematical analysis and numerical results show that this new Rake receiver can achieve larger signal-to-interference-plus-noise ratio than the standard matched filter Rake receiver when multipath components are resolvable in UWB channels. 相似文献
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A linear receiver for digital communication over unknown dispersive and noisy channels obtained by jointly optimizing the prefilter and equalizer has been described by the authors in a recent paper [4]. An extension to incorporating a decision-feedback equalizer is made. Performance of the new receiver is evaluated by means of computer simulation. Comparison of the performance of the new receiver, the matched filter-equalizer receiver, and the fixed low-pass filter-equalizer receiver is made both with respect to convergence rate and error rate. It is conjectured that the new receiver exhibits performance superior to both the matched filter-equalizer receiver and the fixed low-pass filter-equalizer receiver. 相似文献
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A novel receiver structure based on soft-limiting is proposed for detecting a time-hopping ultrawide-bandwidth (UWB) signal in the presence of multiple-access interference (MAI). The proposed structure contains a nonlinear limiter for suppressing the MAI. Simulation results show that the proposed receiver achieves better bit-error-rate performance than the conventional matched receiver when operating in MAI. When operating in an MAI-plus-Gaussian-noise environment, the receiver structure outperforms the conventional matched-filter receiver for moderate to large values of signal-to-noise ratio (SNR). A receiver structure with adaptive limiting threshold is further proposed to ensure that the performance of the soft-limiting receiver always meets or surpasses the performance of the conventional UWB receiver for all values of SNR. Application of the soft-limiting structure in the fingers of a rake receiver is shown to enhance the signal-to-noise-plus-interference ratio. 相似文献
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混合波束赋形在射频模拟域波束赋形的基础上,通过在基带实现数字域波束赋形来进一步提高数据速率.本文针对基于混合波束赋形的室内毫米波MIMO(Multiple Input Multiple Output)系统进行性能分析,分别评估了迫零(Zero Force,ZF)接收机、最小均方误差(Minimum Mean Square Error,MMSE)接收机以及匹配滤波(Matched Filter,MF)接收机在基于码本的最优波束选择下的传输速率,并对接收机在不同的信道环境下进行性能评估.仿真结果表明,无论视距(Line-Of-Sight,LOS)传播路径是否被遮挡,MMSE接收机和ZF接收机在总发射功率较高时均具有接近容量的性能;在总发射功率较低时MMSE接收机的性能则略优于ZF接收机.相反,MF接收机始终保持较差的性能.系统可根据总发射功率大小以及接收机的实现复杂度来选取合适的接收机.本文所研究的系统可应用于实际室内无线个域网(Wireless Personal Area Networks,WPAN)以实现高速短距无线通信. 相似文献
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首先介绍了基于判决自相关(简称DDA)超宽带接收机的接收原理和结构,理论分析了接收误码率特点;比较了基于判决自相关接收机与Rake接收机和基本TR接收机的基本参数要求,并在标准信道模型下仿真对比了它们的接收性能;考察了窗口宽度因子N对基于判决自相关接收机接收性能和结构的影响;通过提高判决自相关系统脉冲功率可在相同能量效率条件下获得与平均TR系统相近的接收性能,且具有更高传输率的优点。 相似文献
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采用LTCC技术的X波段接收前端MCM设计 总被引:2,自引:0,他引:2
多芯片组件(MCM)是目前实现机载雷达接收前端小型化的最有效途径。文中对X波段全频段多功能接收前端的组成、采用LTCC技术的MCM设计实现及实物测试数据进行了叙述和分析,给出了采用LTCC技术的X波段多功能接收前端MCM设计的一种解决方案。该MCM接收前端的测试指标满足雷达通用接收前端要求,为雷达小型化多功能接收前端的设计提供了参考依据。 相似文献
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回顾了电子战接收机特别是电子战数字接收机的发展历程,在此基础上指出宽带数字接收机是电子战接收机的发展趋势,并提出了宽带数字接收机必须要克服的主要技术难题。 相似文献
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A Comparative Analysis of Optimum and Suboptimum Rake Receivers in Impulsive UWB Environment 总被引:3,自引:0,他引:3
Kim B. S. Bae J. Song I. Kim S. Y. Kwon H. 《Vehicular Technology, IEEE Transactions on》2006,55(6):1797-1804
In this paper, the performance of rake receivers in the presence of fading and impulsive noise is addressed. The optimum maximum likelihood (ML) rake receiver for impulsive fading channel is derived, and a suboptimum rake receiver with a reduced complexity is obtained for practical purposes. Numerical results show that the suboptimum rake receiver exhibits almost the same performance as the optimum rake receiver. It is also observed that, as the number of fingers of a rake receiver increases, the performance of the rake receiver designed for impulsive environment improves, while the rake receiver optimized for Gaussian environment experiences performance degradation in an impulsive environment 相似文献
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单比特接收机是一种结构非常简单的数字接收机,他的整个设计可以在一个芯片中完成。本文主要研究了单比特接收机的结构,并对其性能进行了分析。该接收机能够覆盖约1GHz的带宽,并且可以同时处理两个信号。他不仅具有良好的频率分辨率和灵敏度,而且单信号动态范围和双信号无杂散动态范围也比传统的数字接收机大。 相似文献
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Impulse radio is a low-complexity ultra-wideband system which is suitable for highly dispersive multipath channel. In this paper, we propose a random correlation-based receiver for impulse radio communications. The proposed receiver correlates the received pilot symbols with the randomly generated base functions according to channel statistics and forms the detection template by combining several base functions which have larger correlation coefficients with the pilot symbols. The proposed receiver demodulates the received signal by employing a symbol rate sampling. Computer simulation results have shown that the proposed receiver outperforms the conventional correlator-based receiver, compressive sensing correlator-based receiver, weighted energy detector and autocorrelation receiver. 相似文献
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