共查询到18条相似文献,搜索用时 171 毫秒
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为了实现以较低的采样率对超宽带(UWB)脉冲信号进行采样以及在带宽和系统复杂度之间取得均衡,设计了一种基于变换采样的超宽带接收机系统.设计的接收机在AD芯片之前加入了跟踪保持放大器,提高了系统的模拟带宽(5GHz),通过采样时钟的较小延时实现了较高的等效采样率(8 GHz).主要用来接收带宽1 GHz以及以上的超宽带信号,利用VHDL进行编程,通过Chipscope抓取信号进行验证.测试表明,该系统能接收1 GHz以及以上带宽超宽带信号,达到了设计要求,可以用于超宽带通信与测距. 相似文献
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在穿墙雷达(TWR)接收超宽带(UWB)回波信号的过程中,高速信号采集是其中的关键所在。首先基于传统等效采样方法,改进了其采样模式,能极大地提高等效采样的实时性,并减小精密延时电路的延时时间范围。其次利用跟踪保持芯片设计了一种新型等效采样接收机前端实现方案,不仅能降低等效采样技术对取样脉冲的要求,而且能充分发挥跟踪保持芯片高重复频率、高稳定和高度集成的优势。通过分析和仿真论证,实现了10GHz的等效采样频率,理论分析与仿真测试结果一致性良好。这种高度集成、简单高效的电路在超宽带穿墙雷达接收机中具有很好的应用前景。 相似文献
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脉冲超宽带雷达回波信号由于带宽大而难以直接采样,通常采用等效时间采样方法来进行模数转换。传统的等效采样接收机大都是基于改变ADC采样时钟的时延来实现等效采样,采样时钟对触发信号会产生亚稳态时序,不可避免地会出现数据误对齐,必须添加辅助的在线或离线校正设计。针对这一问题,设计了一种基于FPGA内置延迟线的超宽带等效采样接收机,FPGA产生延时可调的发射触发信号去控制波形产生系统,基于高速采样保持器和ADC完成回波接收,实现了超宽带射频信号的等效采样,而无数据误对齐问题。接收机的等效采样速率为12.8GS/s,-3dB采样带宽为6.4GHz,满足脉冲超宽带雷达的应用需求。 相似文献
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传统的信号检测算法基于奈奎斯特采样定理来实现,这对于带宽极宽的超宽带(ultra-wideband,UWB)信号而言由于要求采样速率过高而很难用硬件去实现。为此,本文研究了基于压缩感知(compressive sensing,CS)的脉冲超宽带(impulse radio UWB, IR-UWB)信号检测问题,利用IR鄄UWB 信号在时域上的稀疏特性,设计了一种基于压缩感知的IR鄄UWB 信号检测框架,在此基础上提出了一种自适应加权正交匹配追踪检测算法。仿真结果表明,新算法不仅能够通过远少于奈奎斯特定理所要求的采样速率检测出IR-UWB 信号,而且与基于匹配追踪的压缩感知检测算法相比,新算法在低信噪比的情况下对IR-UWB 信号的检测效果更佳。 相似文献
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脉冲超宽带(IR-UWB)能够在无线定位中取得较高的精确度,但是存在ADC瓶颈问题,利用压缩感知理论(CS)对信号压缩采样可以显著降低信号采样速率。本文将贝叶斯压缩感知应用于UWB单站定位,接收节点利用L型天线阵列接收信号,对信号压缩采样,由贝叶斯压缩感知重构算法(BCS)还原信号并估计时延参数,最后由定位算法解算位置信息。基于IEEE 802.15.4a信号模型的仿真结果表明,该方法最低能以20%的奈奎斯特采样速率获得分米级的定位精确度。 相似文献
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本文研究高速IR-UWB通信中选择性合并Rake接收机(Srake[1])的接收性能.研究结果表明在高速IR-UWB通信中,当合并分支数目增加时,一般SRake接收机的性能不随分集增益升高而变好.本文提出一种基于错误图样正交分集(Orthogonal Diversity Based on Error Samples,ODBES)的SRake接收方法,通过对错误图样的处理消除多径之间的相关性,增加合并信噪比,进而提高系统性能.分析和仿真结果表明,该改进的方法对密集多径环境下高速IR-UWB通信中SRake接收机性能有明显改善,对IR-UWB接收机的设计有实际的应用价值. 相似文献
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在分析各种超宽带(UWB)接收机系统结构的基础上,提出了一种低功耗IR-UWB接收机结构.该结构基于非相干通信机制,使用自混频技术和脉冲宽度调制方式(PPM).在该结构中,低噪声放大器(LNA)的低功耗优化是系统低功耗实现的关键.综合分析各种宽带LNA结构,提出了一种低功耗LNA设计.该LNA采用65 nmCMOS标准... 相似文献
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超宽带CI脉冲是由多个相干载波合成的窄脉冲信号.该文在此基础上,提出了扩频CI合成窄脉冲技术.由此降低了功率谱密度,提高了频带使用效率和便于多址应用.通过对每个相干载波信号CI扩频且合成,其效果很好.在信道传播上拥有超宽带信号的抗多径高分辨率性能,同时又能对扩频相干副载波进行相关接收,这样大大地提高了相关接收增益,减少了码间串扰.该文运用信号最佳设计方法,将超宽带SSCI信号设计成符合FCC标准和ETSI标准的最佳信号,减少与其他无线系统的相互干扰.文中给出了理论分析、设计方法和计算机模拟仿真结果.该设计方法对于提高UWB通信系统的性能有很重要的意义. 相似文献
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ZHENG Sheng-hua XU Da-zhuan JIN Xue-ming 《中国电子科技》2007,5(1):33-37
The developments of the high speed analog to digital converters (ADC) and advanced digital signal processors (DSP) make the smart antenna with digital beamforming (DBF) a reality. In conventional M-elements array antenna system, each element has its own receiving channel and ADCs. In this paper, a novel smart antenna receiver with digital beamforming is proposed. The essential idea is to realize the digital beamforming receiver based on bandpass sampling of multiple distinct intermediate frequency (IF) signals. The proposed system reduces receiver hardware from M IF channels and 2M ADCs to one IF channel and one ADC using a heterodyne radio frequency (RF) circuitry and a multiple bandpass sampling digital receiver. In this scheme, the sampling rate of the ADC is much higher than the summation of the M times of the signal bandwidth. The local oscillator produces different local frequency for each RF channel The receiver architecture is presented in detail, and the simulation of bandpass sampling of multiple signals and digital down conversion to baseband is given. The principle analysis and simulation results indicate the effectiveness of the new proposed receiver. 相似文献
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Won Namgoong 《Wireless Communications, IEEE Transactions on》2003,2(3):502-510
A channelized digital ultrawideband (UWB) receiver that efficiently samples the UWB signal at a fraction of the chip frequency is proposed. The received signal is channelized in the frequency domain by employing a bank of mixers and low-pass filters. After sampling at a much reduced frequency, digital synthesis filters optimally estimate the transmitted signals. The signal-to-noise ratio (SNR) of the proposed receiver has been solved and compared against an ideal conventional receiver, which is defined as a receiver that samples at the signal Nyquist rate. When finite resolution analog-to-digital converters (ADC) are employed in the presence of a large narrowband interferer, the proposed receiver significantly outperforms the ideal conventional receiver. For example, the SNR of the proposed receiver is as much as 20 dB higher than the ideal conventional receiver when a 4-bit ADC is used in the presence of a 50 dB (relative to the noise floor) brickwall narrowband interferer with a bandwidth of 15% of the chip frequency. 相似文献
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基于FPGA高速并行采样技术的研究 总被引:2,自引:1,他引:1
介绍一种基于四通道ADC的高速交错采样设计方法以及在FPGA平台上的实现。着重阐述四通道高速采样时钟的设计与实现、高速数据的同步接收以及采样数据的校正算法。实验及仿真结果表明,同步数据采集的结构设计和预处理算法,能良好抑制并行ADC输出信号因相位偏移、时钟抖动等造成的失配误差。 相似文献
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高速数据采集系统是现代雷达信号处理不可缺少的重要组成部分。文章以宽带侦察接收机信号处理为应用背景,论述了一种基于带通采样的高速数据采集系统的设计方案。该方案以Xilinx公司Virtex-5系列FPGA为平台,控制高速模数转换器ADC08D1000,完成数据采样、传输、存储、信号处理功能,并选取高速FIFO作为存储设备,解决数据率转换问题。该系统实现了软件、硬件设计,测试结果验证了方案的可行性。 相似文献
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Puneet P. Newaskar Raul Blazquez Anantha P. Chandrakasan 《Journal of Signal Processing Systems》2005,39(1-2):175-188
Ultra wideband radio (UWB) is a new wireless technology that uses narrow pulses to transmit information. Implementing an “all-digital” UWB receiver has numerous potential benefits ranging from low-cost and ease-of-design to flexibility. Digitizing an RF signal near the antenna, however, introduces its own set of challenges and has traditionally been considered infeasible. A high-speed, high-resolution analog-digital converter (ADC) is difficult to design, and is extremely power-hungry. The viability of an “all-digital” architecture, therefore, hinges upon the specifications of this block. In this paper, we demonstrate that 4 bits of resolution are sufficient for reliable detection of a typical UWB signal that is swamped in noise and interference. 相似文献
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该文针对超宽带无线通信中需要设计高速模数转换器的问题,提出了一种欠奈奎斯特采样方法,该方法所要求的采样率仅与信号新息率相关,低于奈奎斯特率1个数量级。基于欠采样得到的离散时间超宽带信号,从理论上推导出信号的傅里叶频谱表达式,由此给出了一种总体最小二乘参数估计算法,能够准确地估计出冲激串信号的幅度和时移;通过将估计出的冲激串信号与高斯单脉冲波形卷积,完成超宽带信号的波形重建。仿真和实验结果表明,该文算法能够准确地重建原始超宽带信号,且算法性能优于现有的零化滤波重建算法。 相似文献