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西安交通大学 [1]
长春光学精密机械与物... [1]
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2014 [1]
2010 [1]
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Energy efficient generalised selection combining scheme considering circuit power dissipation
期刊论文
IET COMMUNICATIONS, 2014, 卷号: 8, 期号: [db:dc_citation_issue], 页码: 2652-2658
作者:
Chen, Li
;
Zhang, Chao
;
Wei, Guo
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浏览/下载:2/0
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提交时间:2019/12/03
circuit power dissipation
transmitting antennas
Rayleigh fading channels
Rayleigh channels
order statistics
EE-GSC scheme
radio transmitters
transmit power dissipation
transmitter energy efficiency
spatial diversity
active branches
transmit antennas
energy efficient generalised selection combining scheme
statistical analysis
telecommunication power management
diversity reception
diversity gain
transmit diversity systems
Far-field focusing of laser beam based on digital image processing techniques (EI CONFERENCE)
会议论文
Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China
Zhang H.-Y.
;
Zhao S.
;
Guo J.
;
Liu L.-S.
;
Tian Y.-Z.
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提交时间:2013/03/25
In order to lead the laser beam transmit in the atmosphere convergently
an experiment of laser focus at the distance of 450m and 300m has been operated in the outdoor place. The actual manipulations are as follows: Firstly
the laser was collimated by a beam expander
then the near-parallel laser beam was transmitted with a Galileo telescope system
and the distance between the concave lens and the convex lens can be tuned through a precise displacement platform
so the focus of the system changed due to the tiny displacement of the concave lens. Secondly
the average power of the laser spot can be measured using power meter
the power is 47.67mW and the standard deviation is 0.67mW while the focal length is 450m. Thirdly
the energy distribution was found through the laser beam analyzer. The spot images were saved using the beam analyzer
then the saved image can be processed with Matlab software afterwards. The function named EDGE and Sobel operator was used in the pre-processing of the saved image
then method of median filter was used in the course of image de-noising and 53H filter was adopted in the signal analysis. The diameter of laser spot was obtained by the method above
the diameter is 5.56mm and the standard deviation is 0.24mm. The spot center excursion is 0.56mm
it is 10.43% of the total diameter of the laser spot. At last
the key factors of the energy dissipation in the focusing system can be summarized as follows: restriction of the diffraction limit
attenuation in the atmosphere
geometrical aberration of optical system
and the diffraction limit and the geometrical aberration are significant in the three factors above
so we can reduce the impact of the both factors during the design of optical system. The reliable referenced data of the system design can be acquired through the primary experiment research. 2010 SPIE.
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