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基于数字锁相环的FPGA多通道频率测量系统设计 被引量:5
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作者 金鑫 田文杰 +1 位作者 刘迪 陈福彬 《仪表技术与传感器》 CSCD 北大核心 2022年第2期52-56,共5页
针对传统频率测量电路复杂、采集速度较慢的问题,基于FPGA(现场可编程逻辑门阵列),采用全数字锁相环对待测量信号进行倍频,辅以自适应时钟模块、计数模块和串口接收发送模块,设计了多通道频率测量系统,从而达到精简电路并实现对多路待... 针对传统频率测量电路复杂、采集速度较慢的问题,基于FPGA(现场可编程逻辑门阵列),采用全数字锁相环对待测量信号进行倍频,辅以自适应时钟模块、计数模块和串口接收发送模块,设计了多通道频率测量系统,从而达到精简电路并实现对多路待测信号的快速精准测量。实验结果表明,对于100 Hz~10 MHz频率的稳定信号,测量时间仅为100 ms,与标准频率计相比,相对误差<0.5 ppm(1 ppm=10^(-6))。可用于多路频率信号的实时采集测量。 展开更多
关键词 FPGA 数字锁相环 自适应时钟 多通道频率测量 串口通讯
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Spatial channel characteristics in the outdoor hotspot environment based on wideband MIMO measurements
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作者 高新颖 Zhang Jianhua +1 位作者 Dong Weihui Zhang Ping 《High Technology Letters》 EI CAS 2008年第4期337-341,共5页
Wideband multiple-input multiple-output (MIMO) channel measurements were performed at5.25GHz in the hotspot environment in Beijing.The propagation mechanism was line-of-sight and ob-structed-line-of-sight (LOS/OLOS) i... Wideband multiple-input multiple-output (MIMO) channel measurements were performed at5.25GHz in the hotspot environment in Beijing.The propagation mechanism was line-of-sight and ob-structed-line-of-sight (LOS/OLOS) in the outdoor scenario.Using a large amount of estimated angle ofdeparture (AoD) and angle of arrival (AoA) results,the cumulative distribution functions (CDFs) of di-rectional spread (DS) are extracted,which illustrate that the spatial dispersion is quite significant at bothends due to the low antenna height of base station and rich scatterers.The average power azimuth spec-trum (PAS) is found to be well fitted with a Laplacian function.In addition,the non-isotropic property ofspatial correlation is investigated,and the average envelop correlation over arbitrary antenna spacing pro-vides the correlation distance to facilitate the MIMO optimization and deployment in the outdoor hotspotenvironment. 展开更多
关键词 WIDEBAND multiple-input multiple-output (MIMO) channel measurements directional spread (DS) power azimuth spectrum (PAS) envelope correlation
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