共查询到17条相似文献,搜索用时 140 毫秒
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耦合去耦网络被广泛用于电磁兼容射频传导抗扰度试验,阻抗是其校准的关键参数。为了测量耦合去耦网络的阻抗,适配器被用于连接矢量网络分析仪和耦合去耦网络的受试设备端。目前国内校准实验室普遍没有考虑到适配器对矢量网络分析仪自校准质量的影响,导致高频段阻抗模值测量结果偏差较大。因此,分别基于实验和理论计算原理,设计了同轴转换自校准法和电长度补偿计算修正法用于改善阻抗测量结果。数据表明,上述方法较好地减小了适配器的负面影响,对测量结果起到了改善作用。 相似文献
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《IEEE transactions on instrumentation and measurement》1973,22(1):18-22
A crucial measurement in the Astron device of the controlled thermonuclear research program is to monitor a small (10-G) transient magnetic field caused by a moving group of electrons. The Astron device involves high currents, large magnetic fields, radiation problems, and gigantic radio frequency (RF) noise. The evolution of a Hall device gaussmeter to directly measure this phenomenon is explained. The result is a simple device for the measurement of a small signal buried in noise of the combined form of large magnetic field, RF power, gamma radiation, and high dc currents. 相似文献
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近年来,随着便携式系统和无线通讯系统的迅速发展,电子产品的消费已经转移到射频领域。这为SOI技术的应用开辟了广阔的前景:一方面,由于射频领域的便携式系统和无线通讯系统多数是使用电池作为能源的,因此降低系统功耗和驱动电压就成为需要解决的首要问题。在这方面,SOIcMOS技术由于寄生电容小而成为解决功耗问题的一项关键技术。另一方面,射频领域的发展要求集成水平和工作频率提高,藕合噪声问题变得更加关键。采用全氧隔离的SOICMOS技术实现了器件和基片之间的完全隔离,显著降低了高频RF和数字、混合信号器件之间的串扰现象,从而使藕合噪声问题得到很大改善。文章详细介绍了0.5umSOICMOS的工艺流程,并利用silvaco软件对工艺进行仿真。 相似文献
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文章主要介绍了近年来电火工品瞬态脉冲试验在国内外的发展现状.包括试验仪器、热参数计算和分析的进展,以及瞬态脉冲试验在电火工品质量检测中的作用.收集并分析了瞬态脉冲试验的应用范围和局限性,结合现有的仪器和软件,展望了瞬态脉冲试验今后在硬件和软件方面的发展趋势. 相似文献
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Silicon microfabricated column with microfabricated differential mobility spectrometer for GC analysis of volatile organic compounds 总被引:1,自引:0,他引:1
Lambertus GR Fix CS Reidy SM Miller RA Wheeler D Nazarov E Sacks R 《Analytical chemistry》2005,77(23):7563-7571
A 3.0-m-long, 150-microm-wide, 240-microm-deep channel etched in a 3.2-cm-square silicon chip, covered with a Pyrex wafer, and coated with a dimethyl polysiloxane stationary phase is used for the GC separation of volatile organic compounds. The column, which generates approximately 5500 theoretical plates, is temperature-programmed in a conventional convection oven. The column is connected through a heated transfer line to a microfabricated differential mobility spectrometer. The spectrometer incorporates a 63Ni source for atmospheric-pressure chemical ionization of the analytes. Nitrogen or air transport gas (flow 300 cm(3)/min) drives the analyte ions through the cell. The spectrometer operates with an asymmetric radio frequency (RF) electric field between a pair of electrodes in the detector cell. During each radio frequency cycle, the ion mobility alternates between a high-field and a low-field value (differential mobility). Ions oscillate between the electrodes, and only ions with an appropriate differential mobility reach a pair of biased collectors at the downstream end of the cell. A compensation voltage applied to one of the RF electrodes is scanned to allow ions with different differential mobilities to pass through the cell without being annihilated at the RF electrodes. A unique feature of the device is that both positive and negative ions are detected from a single experiment. The combined microfabricated column and detector is evaluated for the analysis of volatile organic compounds with a variety of functionalities. 相似文献