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浏览/检索结果: 共16条，第1-10条 帮助

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In-orbit Demonstration of X-Ray Pulsar Navigation with the Insight-HXMT Satellite 期刊论文  OAI收割
The Astrophysical Journal Supplement Series, 2019, 卷号: 244, 页码: 1
作者:  HXMT
  |  收藏  |  浏览/下载：15/0  |  提交时间：2022/02/08
pulsars: general  techniques: miscellaneous  Astrophysics -  Instrumentation and Methods for Astrophysics  Abstract: In this work, we report the in-orbit demonstration of X-ray pulsar navigation with Insight-Hard X-ray Modulation Telescope (Insight-HXMT) Satellite, which was launched on 2017 June 15. The new pulsar navigation method Significance Enhancement of Pulse-profile with Orbit-dynamics is adopted to determine the orbit with observations of only one pulsar. In this test, the Crab pulsar is chosen and observed by Insight-HXMT from 2017 August 31 to September 5. Using the five-day long observation data, the orbit of Insight-HXMT is determined successfully with the three telescopes onboard: High Energy X-ray Telescope, Medium Energy X-ray Telescope, and Low Energy X-ray Telescope, respectively. By combining all the data, the position and velocity of the Insight-HXMT are pinpointed to within 10 km (3ҩ and 10 m s-1 (3ҩ, respectively.  
Measuring millimeter-scale distances in a laser self-mixing velocimeter with low-speed wavelength modulation 期刊论文  OAI收割
OPTICS COMMUNICATIONS, 2018, 卷号: 427, 页码: 107-111
作者:  Sun, Wu;  Gui, Huaqiao;  Zhang, Peng;  Wu, Shan;  Li, Zhen
  |  收藏  |  浏览/下载：54/0  |  提交时间：2019/11/11
Quantum key distribution system based on combined modulation 期刊论文  OAI收割
ACTA PHYSICA SINICA, 2013, 卷号: 62, 期号: 13
Guo, BH; Yang, L; Xiang, C; Guan, C; Wu, LA; Liu, SH
收藏  |  浏览/下载：31/0  |  提交时间：2014/01/16
Route of delivering 40-fs ultra-short laser pulses for gating photoconductive antenna in fiber-coupled terahertz time-domain spectroscopy 期刊论文  OAI收割
optical engineering, 2012, 卷号: 51, 期号: 8, 页码: 085001
作者:  Liu, Jia;  Fan, Wen-Hui;  Chen, Long-Chao
收藏  |  浏览/下载：36/0  |  提交时间：2013/07/08
Adjustment of spiral drift by a travelling wave perturbation 期刊论文  OAI收割
NONLINEAR DYNAMICS, 2012, 卷号: 67, 页码: 159-164
作者:  Wu, Ningjie;  Gao, Hongjun;  Ma, Jun;  Ying, Heping
  |  收藏  |  浏览/下载：18/0  |  提交时间：2018/07/05
OFDM baseband modulation technology based on VHDL (EI CONFERENCE) 会议论文  OAI收割
2010 IEEE International Conference on Advanced Computer Control, ICACC 2010, March 27, 2010 - March 29, 2010, 445 Hoes Lane - P.O.Box 1331, Piscataway, NJ 08855-1331, United States
Lin L.; Qiao Y.-F.; Su W.-X.
收藏  |  浏览/下载：16/0  |  提交时间：2013/03/25
In order to improve the transmission velocity in mulitipath fading wireless channel  two main advantages are obtained via discussing spectrum utilization ratio of OFDM. Then  the high speed OFDM technology receives increasing attentions in mobile communication. Modulation programs are designed with VHDL based on the principle of OFDM in the paper. First  from the results of VHDL simulation  after OFDM fundamental is introduced  the realization of baseband operations  such as interleaver  subcarrier modulation  IFFT and adding CP  are presented. Finally  implemented programs are validated on the actual implement system. Experimental results indicate that setup time corresponding to transmission velocity is only 71.05s and steady time is approximately 6 times as setup time  that is  not only achieving the high speed transmission  but also supplying adequate modulation time. 2010 IEEE.  
Estimation algorithm of mobile OFDM CFOs based on step-size (EI CONFERENCE) 会议论文  OAI收割
2009 International Conference on Information Engineering and Computer Science, ICIECS 2009, December 19, 2009 - December 20, 2009, Wuhan, China
Lin L.; Qiao Y.-F.; Su W.-X.
收藏  |  浏览/下载：26/0  |  提交时间：2013/03/25
In order to maintain orthogonality among subcarriers for mobile OFDM  a CFOs step-size estimation model is established to avoid severe performance degradation caused by ICI  and algorithmic stability  step-size parameter  the error of CFOs estimate and etc are investigated. First  after an averaging window algorithm is introduced  the mathematic model of step-size estimation algorithm is obtained through step-size parameter and time-varying CFOs. Then  based on the results of MATLAB simulation  the determination of step-size parameter  the advantages of step-size algorithm and precision are discussed. Finally  time sequence plots of added CP  interleaver and subcarrier modulation with VHDL are presented. Experimental results indicate that the maximum of CFOs errors is 0.00987 in 3 variance interval  when mobile velocity is 400 km/h  according with verdicted principle that in order for the ICI effects to be negligible  the error of CFOs estimation must be accurate within 1-2% of the subcarrier spacing  and programs can correctly implement on circuit board. 2009 IEEE.  
Wavelength conversion based on degenerate-four-wave-mixing with continuous-wave pumping in silicon nanowire waveguide 期刊论文  OAI收割
optics communications, 2009, 卷号: 282, 期号: 8, 页码: 1659-1663
作者:  Chen P;  Zhang L
收藏  |  浏览/下载：222/64  |  提交时间：2010/03/08
Low drive-voltage and high-bandwidth electro-optic modulators based on BaTiO3 thin-film waveguides (EI CONFERENCE) 会议论文  OAI收割
Science and Technology of Dielectrics for Active and Passive Photonic Devices - 210th Electrochemical Society Meeting, October 29, 2006 - November 3, 2006, Cancun, Mexico
Sun D. G.; Fu X. H.; Liu Z. F.; Ho S. T.; Wessels B. W.
收藏  |  浏览/下载：46/0  |  提交时间：2013/03/25
We investigated electro-optic modulator structures to target low drive voltage  high-speed modulation  and small device size with c-axis grown BaTiO3/MgO ferro-electric thin films. In this study  the calculations are focused on the ideal thin film with a quadratic relation between the half-wave drive voltage V and the interaction length L in the electro-optic modulation case we obtained in previous work. With the quadratic electro-optic modulating relation and the optimal rib waveguide structure of BaTiO3/MgO thin films  the frequency-voltage-size performances for 2.5GHz  10GHz  40GHz  and 100GHz modulation bandwidths have been obtained under half-wave drive voltages of 0.8V  1.6V  3.0V and 4.8V  respectively  for the ideal film with r51=730 pm/V at 1550nm wavelength  where both the phase velocity matching condition and the conductor induced microwave attenuation are considered. The required device lengths to achieve these four typical values of modulation bandwidth are 3.3 mm  0.8 mm  0.4 mm and 0.2 mm  respectively. With the c-axis grown BaTiO3/MgO crystal thin films and the quadratic electro-optic modulating relation  an electro-optic coefficient of reff=180 pm/V for the c-axis grown BaTiO3/MgO ferro-electric thin films was measured  which is relatively far from the ideal value of r51=560 pm/V. copyright The Electrochemical Society.  
基于频域相位共轭技术的交叉相位调制所致失真的复原 期刊论文  OAI收割
物理学报, 2005, 卷号: 54, 期号: 10, 页码: 4747, 4753
步扬; 王向朝
收藏  |  浏览/下载：1467/207  |  提交时间：2009/09/18