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STX-2型手持式动态线径测量仪
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作者 施汉生 《电工技术杂志》 1991年第2期33-34,共2页
在拉制裸铜丝、电阻丝等金属丝过程中常常面临测量其直径的误差问题,由于拉丝时金属丝的线速度很高,采用普通量具是无法进行测量的。虽然采用电子测量仪器能够满足生产要求,但是成本高,操作复杂,对于一般中小企业来说日前还不具备这样... 在拉制裸铜丝、电阻丝等金属丝过程中常常面临测量其直径的误差问题,由于拉丝时金属丝的线速度很高,采用普通量具是无法进行测量的。虽然采用电子测量仪器能够满足生产要求,但是成本高,操作复杂,对于一般中小企业来说日前还不具备这样的条件。为此我们设计了与千分表配套的机械式测量装置。1.测量原理测量原理见图1。首先将高速移动的金属丝5嵌入导向轮4、8槽中。 展开更多
关键词 裸铜丝 线径测量仪 手持式
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Path loss modelling and comparison based on the radio propagation measurement at 3.5GHz 被引量:4
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作者 王萍 Li Yingzhe +2 位作者 Chang Ruoting Sun Kun Xu Hui 《High Technology Letters》 EI CAS 2009年第3期272-276,共5页
Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristi... Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristics are proposed for the field test of Chinese 4th generation (4G) trial system. The mea- surement system is established for 3.5GHz based on the sophistieated measurement instruments and the virtual instrument teehnology. The characteristic parameters of radio propagation sueh as path loss (PL) exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our mea- surement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim (SUI) model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the mea- surement result in the suburban scenario. This result provides a measurement-based channel referenee for the development of the future IMT-Advanced systems in China. 展开更多
关键词 IMT-advaneed channel measurement channel model path loss radio propagation Stanford University Interim (SUI) COST 231 Hata WINNER
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