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通过自建电路实现超低频信号相位差测量仪器的校准
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作者 贺晓雷 王拂为 《气象水文海洋仪器》 2006年第2期25-30,共6页
本文介绍了一种根据校准工作的特点,采用自建电路低成本实现超低频信号相位差测量仪器校准的有效方法。在实际工作中,可以大幅降低仪器设备的购置费用。
关键词 低成本 自建电路 超低频信 相位差 校准
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Review of through-the-earth communication technologies
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作者 HAO Jian-jun GONG Yu-qin 《Journal of Measurement Science and Instrumentation》 CAS 2014年第2期64-67,共4页
In this paper, development of through-the-earth communication technologies is summarized, as well as the operating principles and performances. The propagation loss, frequency band and power efficiency are also analyz... In this paper, development of through-the-earth communication technologies is summarized, as well as the operating principles and performances. The propagation loss, frequency band and power efficiency are also analyzed. We can know that among these technologies, the antenna induction method is more popular, but the communication system with ground electrodes is more promising due to its high energy efficiency. The communication with elastic wave (seismic) is not suitable for emergency communication when the accidents of rock burst or land slide occur. 展开更多
关键词 through-the-earth communication very low frequency transmission attenuation
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