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在处理全球卫星导航系统(Global Navigation Satellite System,GNSS)卫星信号时,针对模数转换器(Analog-to-Digital Converter,ADC)量化位数不同导致输出的信号信噪比下降的问题,推导了阵列天线波束形成后输出信号的信噪比理论计算模型,分析了ADC量化位数对阵列天线抗干扰GNSS接收机的性能影响。在7阵元天线且ADC量化位数为10的条件下,理论模型分析和数据仿真结果表明最大抗干扰能力约为85 dB。通过确定ADC量化位数与抗干扰GNSS接收机抗干扰能力之间的关系,其结论为工程应用中抗干扰GNSS接收机的ADC选型和设计提供了理论依据。 相似文献
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本文指出了所谓调相负反馈接收机就是调相信号的准最佳接收机,它可由按最大后验概率估计推导出的最佳接收机模型或按瞬时最大似然估计推导出的最佳接收机模型退化而得到。本文总结了有关方面的文献,对该接收机的性能进行了分析,提出了在高信噪比条件下设计接收机的注意事项。并对主要误差源进行了分析,列举了一些测试结果。 相似文献
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针对传统的发射参考接收机系统资源利用率低,带噪的解调模板使接收机性能下降的缺点,文章给出了一种低复杂度的DT(dirty template)接收机.该接收机利用多个已判决的符号接收波形提取解调模板,一方面降低了解调模板信号中的噪声,另一方面省去了参考信号占用的能量和时间资源,达到了满数据发送率.文章从理论上分析了DT接收机的性能,仿真结果证明了理论推导的正确性. 相似文献
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针对窄带零中频接收机存在的IQ不平衡问题,设计实现了一种基于信号统计的IQ不平衡校准方法。首先建模分析了IQ不平衡对接收机性能的影响,在此基础上使用基于信号统计的方法对幅度和相位不平衡参数进行估计,进而实现IQ不平衡的补偿。实验测试表明,本文所设计算法能够有效实现窄带零中频接收机IQ不平衡的校准。 相似文献
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辐射源个体识别(Specific Emitter Identification,SEI)技术利用辐射源指纹特征识别发射设备,但辐射源指纹特征极易受接收机畸变的影响,无法在不同接收设备间通用.针对这一问题,基于一种利用调制畸变的辐射源个体识别方法,分析了接收机畸变对该方法特征识别结果的影响,得到了接收机畸变特性与特征估计结果的准确数学模型;并将推导结果与接收机设计指标相对应,对SEI接收机设计提出了建议;利用仿真实验和设计实例,证明了推导结果的准确性.该成果能够有效指导SEI系统接收机设计,并为跨接收机SEI系统的实现提供了可能. 相似文献
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由于其较低的成像成本和较强的鲁棒性,使得利用多发射机和多接收机对目标进行有效观测的分布式无源雷达成为雷达技术研究的热门领域。本文在分布式雷达稀疏成像模型基础上,提出一种分布式无源雷达成像接收机配置优化方法,以成像分辨率最高为优化目标函数,针对不同发射机布局采用遗传算法计算出最优接收机布局。同时针对正交匹配追踪(Orthogonal Matching Pursuit, OMP)算法在低信噪比下成像精度较低,信号估计不准确的情况,推导出用协方差稀疏表示接收信号,利用稀疏贝叶斯学习(Sparse Bayesian Learning, SBL)进行信号重构的成像算法,并通过仿真实验对成像性能的改善进行了验证。 相似文献
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A theory for the signal-to-noise ratio (SNR) of optical direct-detection receivers employing return-to-zero (RZ) coding (and possibly optical preamplification) is developed. The results are valid for both signal-independent noise limited and signal-dependent noise limited receivers, as well as for arbitrary optical pulse shapes and receiver filter characteristics. Even if the same receiver bandwidth is used, RZ coding is seen to perform better than nonreturn-to-zero (NRZ) coding. Asymptotic expressions for the SNR in case of very high and very low receiver bandwidths show that the full sensitivity enhancement potential of RZ coding is exhausted at fairly moderate duty cycles. A realistic example taking into account intersymbol interference (ISI) shows that a receiver sensitivity gain (compared to NRZ coding) of, e.g., 3.2 dB can be obtained in a signal-independent noise limited receiver with a bandwidth of 80% of the data rate, using a duty cycle of three 相似文献
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The theory of noise-alone-reference (NAR) power estimation is extended to the estimation of spatial covariance matrices. A NAR covariance estimator insensitive to signal presence is derived. The SNR (signal-to-noise ratio) loss incurred by using this estimator is independent of the input SNR and is less than that encountered with the maximum likelihood covariance estimator given that the same number of uncorrelated snapshots is available to both estimators. The analysis assumes first a deterministic signal. The results are extended and generalized to signals with unknown parameters or random signals. For the random signal case, generalized and quasi-NAR covariance estimators are presented 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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This paper handles the problem of detecting signals with known signature and unknown or random amplitude and phase in the presence of compound-Gaussian disturbance with known spectral density. Two alternative approaches are investigated: the Neyman-Pearson criterion and the generalized likelihood ratio strategy. The first approach leads to a hardly implementable detector but provides an upper bound for the performance of any other detector. The generalized likelihood ratio strategy, instead, leads to a canonical detector, whose structure is independent of the disturbance amplitude probability density function. Based on this result, the threshold setting, which is itself independent on both the noise distribution and the signal parameters, ensures a constant false alarm rate. Unluckily, this receiver requires the averaging of infinitely many components of the received waveform. This is not really a drawback since a close approximation can be found for a practical implementation of the receiver. The performance analysis shows that the generalized likelihood ratio test (GLRT) detector suffers a quite small loss with respect to the optimum Neyman-Pearson receiver (less than 1 dB in the case of random amplitude) and largely outperforms the conventional square-law detector 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》1979,25(6):743-745
A generalized measure of receiver output signal-to-noise ratio (SNR) that includes several conventional measures of SNR as special eases is presented. The potential for anomalous behavior of the new measure when used to predict signal-detection performance is demonstrated through detailed performance analysis of quadratic receivers for incoherent slow- and fast-fading Gaussian channels. 相似文献
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Subspace-based adaptive generalized likelihood ratio detection 总被引:1,自引:0,他引:1
Subspace-based adaptive detection performance is examined for the generalized likelihood ratio detector based on Wilks' Λ statistic. The problem considered here is detecting the presence of one or more signals of known shape embedded in Gaussian distributed noise with unknown covariance structure. The data is mapped into a subspace prior to detection. The probability of false alarm is independent of the subspace transformation and depends only on subspace dimension. The probability of detection depends on the subspace transformation through a nonadaptive signal-to-noise ratio (SNR) parameter. Subspace processing results in an SNR loss that tends to decrease performance and a gain in statistical stability that tends to increase performance. It is shown that the statistical stability effect dominates the SNR loss for short data records, and subspace detectors can require substantially less SNR than full space detectors for equivalent performance. A method for designing the subspace transformation to minimize the SNR loss is proposed and illustrated through simulations 相似文献
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A uniformly most-powerful test does not exist for the problem of detecting a sinusoid of unknown amplitude, phase, and frequency in complex white Gaussian noise of unknown variance. The problem is shown to be invariant to scale and modulation transformations. Using invariance principles, it is found that the uniformly most-powerful-invariant (UMPI) test does not exist. A test is derived that is UMPI if it is given that the signal-to-noise ratio (SNR) is known. For SNR unknown, the derived test can be used as an upper performance bound for any invariant test. Suboptimal tests are typically implemented such as the generalized likelihood ratio and locally most powerful tests, which are also scale and modulation invariant. It is shown analytically that as SNR approaches zero, the locally most-powerful-invariant test performance approaches the UMPI performance bound, and as the SNR becomes large, the generalized likelihood ratio test performance approaches the performance of the UMPI bound. Computer simulation examples indicate that the generalized likelihood ratio test performance is close to the UMPI bound, particularly in the low-probability-of-false-alarm region of the receiver operating characteristic curve 相似文献
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On SNR Estimation Techniques for Turbo Decoding Over Uncorrelated Rayleigh Fading Channels With Unknown Fading Parameters 总被引:1,自引:0,他引:1
《Vehicular Technology, IEEE Transactions on》2009,58(9):4955-4961
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Mohammadali Mohammadi Zahra Mobini Mehrdad Ardebilipour Behrad Mahboobi 《Wireless Personal Communications》2013,72(1):49-70
In this paper, we analyze the performance of multi-hop multi-branch amplify-and-forward (AF) networks over generalized fading channels. Using the moment generating function (MGF)-based approach, we develop general expressions for the outage probability and symbol-error rate (SER) performance of the system with maximal ratio combining (MRC) receiver. The MGF-based approach relies on numerical integration. To gain insights into system performance, we therefore investigate the asymptotic outage and SER performance of the system with MRC and selection combining (SC) receiver at the destination. In particular, we develop the asymptotic statistics of the end-to-end signal-to-noise ratio (SNR) of an AF multi-hop link. We further derive the cumulative density function of the sum of the individual end-to-end SNRs, received from different diversity paths for MRC receiver. We also study the power allocation problem in a multi-hop multi-branch system with MRC receiver. In generalized Gamma fading environments, we seek to find the power allocation strategy that maximizes the SNR at the destination subject to a total power constraint. By means of simulations, we validate our theoretical developments and verify the efficiency of our proposed power allocation in improving the received SNR compared to a generic cooperative system with no power allocation. We also conclude that our asymptotic expressions for the outage probability and SER match the simulations very well in medium-to-high-SNR regime. 相似文献