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有线电视系统前端设备电源自动开关装置
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作者 孙祯祥 《现代教育技术》 1994年第1期34-35,共2页
有线电视系统及卫星电视系统的前端设备往往是昼夜开机的,即使是有人值班的情况下一般也不停机。这样就大大缩短了前端设备的寿命,例如我院的卫星电视接收机连续运行仅一年就发生了故障。因此,笔者研制了一种具有电枧场强仪和电源自动... 有线电视系统及卫星电视系统的前端设备往往是昼夜开机的,即使是有人值班的情况下一般也不停机。这样就大大缩短了前端设备的寿命,例如我院的卫星电视接收机连续运行仅一年就发生了故障。因此,笔者研制了一种具有电枧场强仪和电源自动开关两种功能的电子装置,它能在某一频道的电视信号消失几分钟后自动切断前端设备的供电,使机器设备得到休息;而在电视信号出现时,又能立即接通设备的电源。装置的场强仅部分具有完全独立的使用功能,它与自动开关部分仅有信号与电源的连接,在线路寻修时,场强仪可以方便地使用和携带。 展开更多
关键词 自动开关 有线电视系统 设备电源 系统前端 前端设备 电视场强仪 电视信号 卫星电视接收机 电子装置 接通设备
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Multiband printed monopole and dipole antenna with square-nested fractal
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作者 王丽娜 林澍 +2 位作者 蔡闰南 黄冠龙 张文彬 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第6期53-58,共6页
A kind of novel muhiband antenna with square-nested fractal is proposed and designed, including printed monopole antenna and dipole antenna, which are nested with a series of similar square elements. The antennas can ... A kind of novel muhiband antenna with square-nested fractal is proposed and designed, including printed monopole antenna and dipole antenna, which are nested with a series of similar square elements. The antennas can synchronously operate in multiple frequencies, covering the four required frequencies, 2.4GHz/ 3.5GHz/5.2GHz/5.8GHz, for WLAN/WiMAX application. The antenna surface currents are simulated by CST MWS, a three-dimension full-wave electromagnetic simulator, and the multiband operating mechanism has been explained from analysis of the simulation results. Then the models of the two proposed antennas fed by coplanar waveguide (monopole antenna) and balanced microstripline (dipole antenna), respectively, have been obtained. Finally, prototypes of the two antennas have been manufactured and measured in anechoic chamber. The results well match the simulation results, which verifies the feasibility of design idea. Moreover, these antennas are miniature and the design idea can be easily applied into other types of nested structure, the features of which make the Proposed antennas have promising application in muhiband fields. 展开更多
关键词 multiband antenna fractal antenna coplanar waveguide balanced microstripline nested structure
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