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远距离超声检测技术研究与实现 被引量:1
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作者 何凯 谷立臣 +1 位作者 王柯渊 寇雪芹 《仪表技术与传感器》 CSCD 北大核心 2019年第3期82-85,90,共5页
针对塔机主动防碰撞预警系统中超声检测技术瓶颈问题,设计了远距离超声检测系统架构,开发了远距离超声检测装置,提出了远距离振动模型延时估计方法。该系统主要由超声换能器、微控制器模块、超声信号激励模块、超声信号调理模块、温度... 针对塔机主动防碰撞预警系统中超声检测技术瓶颈问题,设计了远距离超声检测系统架构,开发了远距离超声检测装置,提出了远距离振动模型延时估计方法。该系统主要由超声换能器、微控制器模块、超声信号激励模块、超声信号调理模块、温度补偿模块等构成。在传统阈值法的基础上,根据超声换能器振动时域波形上升沿特征识别超声回波信号,并由此估计超声回波起始位置。试验研究结果表明,该装置利用振动模型延时估计方法,可以精确、稳定、可靠地实时检测距离为33 m的障碍物。 展开更多
关键词 塔吊 长距离 超声检测 振动模型 延时估计法
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Stochastic Analysis of Interconnect Delay in the Presence of Process Variations 被引量:3
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作者 李鑫 Janet M.Wang +1 位作者 唐卫清 吴慧中 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第2期304-309,共6页
Process variations can reduce the accuracy in estimation of interconnect performance. This work presents a process variation based stochastic model and proposes an effective analytical method to estimate interconnect ... Process variations can reduce the accuracy in estimation of interconnect performance. This work presents a process variation based stochastic model and proposes an effective analytical method to estimate interconnect delay. The technique decouples the stochastic interconnect segments by an improved decoupling method. Combined with a polynomial chaos expression (PCE), this paper applies the stochastic Galerkin method (SGM) to analyze the system response. A finite representation of interconnect delay is then obtained with the complex approximation method and the bisection method. Results from the analysis match well with those from SPICE. Moreover, the method shows good computational efficiency, as the running time is much less than the SPICE simulation's. 展开更多
关键词 coupled interconnects process variations stochastic modeling delay estimation stochastic Galerkin method polynomial chaos expression
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CHANNEL ESTIMATION OF MULTI-RATE DS-CDMA SIGNALS IN SLOW FADING MULTIPATH CHANNELS
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作者 Zhang Yingguang Zhang Linrang Liao Guisheng (National Key Laboratory for Radar Signal Processing, Xidian University, Xi’an 710071) 《Journal of Electronics(China)》 2003年第5期321-325,共5页
In Direct-Sequence Code Division Multiple Access(DS-CDMA) mobile communi-cation systems, it is very important to obtain accurate estimation of the channel parameters,especially that of the propagation delay. But the n... In Direct-Sequence Code Division Multiple Access(DS-CDMA) mobile communi-cation systems, it is very important to obtain accurate estimation of the channel parameters,especially that of the propagation delay. But the near-far problem may make the estimationcomplicated and can degrade the estimation performance significantly. In this paper, an efficientMaximum Likelihood (ML) method is presented for channel parameter estimation of multi-rateDS-CDMA systems in slow fading multipath channels in a near-far scenario. The algorithmextended the ML approach to multi-rate DS-CDMA systems, and proposes decomposing a multi-dimensional optimization problem into a series of one-dimensional optimization and has improvedcomputational efficiency. Theoretical analysis and numerical examples show that the estimatorproposed is effective and near-far resistant. 展开更多
关键词 CDMA Channel estimation MULTI-RATE Near-far problem Maximum likelihood CORRELATOR
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