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Spectrum sensing is an essential ability to detect spectral holes in cognitive radio (CR) networks. The critical challenge to spectrum sensing in the wideband frequency range is how to sense quickly and accurately. Compressive sensing(CS) theory can be employed to detect signals from a small set of non-adaptive, linear measurements without fully recovering the signal. However, the existing compressive detectors can only detect some known deterministic signals and it is not suitable for the time-varying amplitude signal, such as spectrum sensing signals in CR networks. First, a model of signal detect is proposed by utilizing compressive sampling without signal recovery, and then the generalized likelihood ratio test (GLRT) detection algorithm of the time-varying amplitude signal is
derived in detail. Finally, the theoretical detection performance bound and the computation complexity are analyzed. The comparison between the theory and simulation results of signal detection performance over Rayleigh and Rician channel demonstrates the validity of the performance bound. Compared with the reconstructed spectrum sensing detection algorithm, the proposed algorithm greatly reduces the data volume and algorithm complexity for the signal with random amplitudes. 相似文献
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在实现教字信道化的原理的基础上,详细分析使用短时傅立叶变换(STFT)方法实现数字信道化,并通过计算机仿真,验证基于STFT实现数字信道化的正确性和可行性,实验证明:该算法简单,易于实现. 相似文献
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在实现数字信道化的原理的基础上,详细分析使用短时傅立叶变换(STFT)方法实现数字信道化,并通过计算机仿真,验证基于STFT实现数字信道化的正确性和可行性,实验证明:该算法简单,易于实现。 相似文献
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宽带信号被广泛应用于雷达、导航和卫星通讯系统等。而线性调频信号(LFM)由于其容易产生跟处理,并且具有大时宽带宽积,而备受关注。文中用去斜脉冲压缩处理方法处理线性调频信号。并且提出了具体的改进方法,利用多相滤波的方法,降低了数据率,解决了高速率模数转换(ADC)与和数字信号处理器件之间的速度不匹配的矛盾。本文通过MATLAB仿真实现了对中心频率在1200 MHz、带宽为1000 MHz、脉冲宽度为40μs的线性调频信号进行去斜处理,在大幅度降低数据率的情况下,实验结果良好,具有可行性和实用性。 相似文献
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基于DDS的频谱分析仪设计 总被引:2,自引:0,他引:2
设计了基于直接数字频率合成(DDS)的频谱分析仪.它依据外差原理,实现频率范围为1~30 MHz的信号频谱分析.通过采用DDS专用器件AD9851产生稳定的扫频信号.被测信号是经AD835与本振信号混频,再放大,滤波,检波的信号.将被测信号与扫频信号分别输入示渡器的X,Y端,即可获得频谱图.此外,该仪器还具有识别调幅,调频和等幅波信号及测定其中心频率的功能. 相似文献
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Li Li Tian-shuang Qiu De-rui Song 《AEUE-International Journal of Electronics and Communications》2013,67(11):947-954
This paper takes the alpha-stable distribution as the noise model and works on the parameter estimation problem of wideband bistatic Multiple-Input Multiple-Output (MIMO) radar system in the impulsive noise environment. In many applications, it is not appropriate to approximate the wideband signal by the narrowband model. Furthermore, the echo signal may be corrupted by the non-Gaussian noise. The conventional algorithms degenerate severely in the impulsive noise environment. Thus, this paper proposes a new wideband signal model and a novel method in wideband bistatic MIMO radar system. It combines the fractional lower order statistics and fractional power spectrum, for suppressing the impulse noise and estimating parameters of the target. Firstly, a new signal array model is proposed under the alpha-stable distribution noise model. Secondly, Doppler stretch and time delay are jointly estimated by peak searching of the FLOS-FPSD. Furthermore, two modified algorithms are proposed for the estimation of the direction-of-departure and direction-of-arrival, including the fractional power spectrum density based on MUSIC algorithm (FLOS-FPSD-MUSIC) and the fractional lower-order ambiguity function based on ESPRIT algorithm (FLOS-FPSD-ESPRIT). Simulation results are presented to verity the effectiveness of the proposed method. 相似文献
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泰克公司(Tektronix)日前推出全新系列实时频谱分析仪,为测量当前复杂的RF信号提供了第一个完整的测量套件. 相似文献
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系统以单片机STM32F407,FPGA为主控单元,采用AD9958产生本振信号,经乘法器与被测信号混频,再结合滤波、放大、A/D转换过程,实现对80~100 MHz频段的频谱分析,并在FTF触屏上显示频谱.实验表明,系统控制方式灵活,实用性较强,具有很好的通用性和推广前景. 相似文献
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运用无记忆非线性变换法及海杂波后向散射系数模型产生了基于Weibull分布、高斯谱的相干海杂波信号,仿真结果符合理论分析,并可以直接应用于脉冲压缩雷达模拟器的仿真中。 相似文献
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基于MP分解的宽带LFM信号参数估计 总被引:2,自引:0,他引:2
将MP分解应用于宽带阵列信号处理中,提出一种针对线性调频信号(LFM)参数估计新算法.根据LFM信号形式建立过完备原子库Gf,其中原子参数由起始频率和调频斜率决定,将阵列参考阵元接收数据在Gf上作MP分解,获得各个信号的起始频率和调频斜率参数,从而得到宽带信号的具体形式;在上一步频率参数估计的基础上,根据阵列结构建立过完备原子库Gθ,其中原子参数由到达角决定,将阵列全部阵元接收数据在Gθ上作MP分解,实现信号DOA估计.新算法估计性能优于传统空间时频分布(STFD)方法,尤其在低信噪比、多信源情况下仍然有较高的估计精度.计算机仿真结果验证了算法的有效性. 相似文献
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在认知无线电(CR)网络中进行频谱共享接入,首要的任务是进行频谱感知,并发现频谱空洞。基于认知无线网络中信号频域的固有稀疏性,本文结合了压缩感知(CS)技术与加权平均一致(weighted average consensus)算法,建立了分布式宽带压缩频谱感知模型。频谱感知分为两个阶段,在感知阶段,各个CR节点对接收到的主用户信号进行压缩采样以减少对宽带信号采样的开销和复杂度,并做出本地频谱估计;在信息融合阶段,各CR节点的本地频谱估计结果以分布式的方式进行信息融合,并得到最终的频谱估计结果,获得分集增益。仿真结果表明,结合压缩感知与加权平均一致算法增强了频谱感知的性能,比在相同的CR网络中使用平均一致算法时有了性能上的提升。 相似文献