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Accurate and robust estimation of phase error and its uncertainty of 50 GHz bandwidth sampling circuit

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Science in China(Series F) 2007年第6期50卷 905-914页

作者： ZHANG Zhe LIN MaoLiu XU QingHua TAN JiuBin Department of Electronics and Communication Harbin Institute of Technology Harbin 150001 China

This paper discusses the dependence of the phase error on the 50 GHz bandwidth oscilloscope＇s sampling circuitry. We give the definition of the phase error as the difference between the impulse responses of the NTN （nose-to-nose） estimate and the true response of the sampling circuit. We develop a method to predict the NTN phase response arising from the internal sampling circuitry of the oscilloscope. For the default sampling-circuit configuration that we examine, our phase error is approximately 7.03° at 50 GHz. We study the sensitivity of the oscilloscope＇s phase response to parametric changes in sampling-circuit component values. We develop procedures to quantify the sensitivity of the phase error to each component and to a combination of components that depend on the fractional uncertainty in each of the model parameters as the same value, ±10%. We predict the upper and lower bounds of phase error, that is, we vary all of the circuit parameters simultaneously in such a way as to increase the phase error, and then vary all of the circuit pa- rameters to decrease the phase error. Based on Type B evaluation, this method qualifies the impresses of all parameters of the sampling circuit and gives the value of standard uncertainty, 1.34°. This result is developed at the first time and has important practical uses. It can be used for phase calibration in the 50 GHz bandwidth large signal network analyzers （LSNAs）.

关键词： uncertainty phase error sampling oscilloscope

Generic nonlinear error compensation algorithm for phase measuring profilometry

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Chinese Optics Letters 2021年第10期19卷 19-23页

作者：于馨赖姗姗刘元坤陈文静薛俊鹏张启灿 Opto-Electronic Department Sichuan UniversityChsngdu 610065China School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China

In this Letter,the periodical errors,which are caused by the nonlinear effect of the commercial projector and camera,are analyzed as a more generic single-coefficient *** probability density function of the wrapped phase distributions is used as a tool to find the compensation *** the compensation coefficient is detected,on the premise of ensuring accuracy,a correlation algorithm process is used to replace the traditional iterative ***,the proposed algorithm improves the efficiency of coefficient detection *** computer simulation and experiment show the effectiveness of this method.

关键词： nonlinear response phase error probability density function three-dimensional sensing

Solar image reconstruction method under atmospheric turbulence at Fuxian Lake Solar Observatory

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Astronomical Techniques and Instruments 2024年第2期1卷 128-139页

作者： Sizhong Zou Zhenyu Jin Kaifan Ji Jun Xu Lei Yang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China University of Chinese Academy of Sciences Beijing 101408China

Strong atmospheric turbulence reduces astronomical seeing,causing speckle images acquired by ground-based solar telescopes to become blurred and *** distortion in speckle images impedes image phase deviation in the speckle masking reconstruction method,leading to the appearance of spurious imaging *** only on linear image degradation principles to reconstruct solar images is *** solve this problem,we propose the multiframe blind deconvolution combined with non-rigid alignment(MFBD-CNRA)method for solar image *** consider image distortion caused by atmospheric turbulence and use non-rigid alignment to correct pixel-level distortion,thereby achieving nonlinear constraints to complement image intensity *** creating the corrected speckle image,we use the linear method to solve the wavefront phase,obtaining the target *** verify the effectiveness of our method results,compared with others,using solar observation data from the 1 m new vacuum solar telescope(NVST).This new method successfully reconstructs high-resolution images of solar observations with a Fried parameter r0 of approximately 10 cm,and enhances images at high *** r0 is approximately 5 cm,the new method is even more *** reconstructs the edges of solar graining and sunspots,and is greatly enhanced at mid and high frequency compared with other *** confirm the effectiveness of this method,with respect to both nonlinear and linear constraints in solar image *** provides a suitable solution for image reconstruction in ground-based solar observations under strong atmospheric turbulence.

关键词： Astronomical seeing Solar telescopes Solar observatories Astronomy image processing phase error Deconvolution

Forward link outage performance of aeronautical broadband satellite communications

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Frontiers of Information Technology & Electronic Engineering 2021年第6期22卷 790-801页

作者： Huaicong KONG Min LIN Shiwen HE Xiaoyu LIU Jian OUYANG Weiping ZHU College of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China School of Computer Science and Engineering Central South UniversityChangsha 410083China Purple Mountain Laboratories Nanjing 210096China Department of Electrical and Computer Engineering Concordia UniversityMontrealQC H3G 1M8Canada

High-throughput satellites(HTSs) play an important role in future millimeter-wave(mm Wave) aeronautical communication to meet high speed and broad bandwidth requirements. This paper investigates the outage performance of an aeronautical broadband satellite communication system’s forward link, where the feeder link from the gateway to the HTS uses free-space optical(FSO) transmission and the user link from the HTS to aircraft operates at the mm Wave band. In the user link, spot beam technology is exploited at the HTS and a massive antenna array is deployed at the aircraft. We first present a location-based beamforming(BF) scheme to maximize the expected output signal-to-noise ratio(SNR) of the forward link with the amplify-and-forward(AF) protocol,which turns out to be a phased array. Then, by supposing that the FSO feeder link follows Gamma-Gamma fading whereas the mm Wave user link experiences shadowed Rician fading, we take the influence of the phase error into account, and derive the closed-form expression of the outage probability(OP) for the considered system. To gain further insight, a simple asymptotic OP expression at a high SNR is provided to show the diversity order and coding gain. Finally, numerical simulations are conducted to confirm the validity of the theoretical analysis and reveal the effects of phase errors on the system outage performance.

关键词： Aeronautical broadband satellite network Free-space optical(FSO)transmission High throughput mmWave communication Outage probability phase error

Performance of an M-QAM full-duplex wireless system with a nonlinear amplifier

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Science China(Information Sciences) 2016年第10期59卷 103-111页

作者： Zhaojun HE Wanzhi MA Shihai SHAO Fei WU Chaojin QING Youxi TANG National Key Laboratory and Technology on Communications University of Electronic Science and Technology of China School of Electrical and Information Engineering Xihua University

The effect of amplifier nonlinearity is analyzed for M-QAM full-duplex communications in additive white Gaussian noise channels. Two classical memoryless nonlinear amplifier models, i.e., a traveling-wave tube amplifier and a solid-state power amplifier, are considered. An analytical expression for the bit error ratio is derived using a characteristic function and numerical integration. Theoretical results show perfect agreement with those obtained by simulation. The analytical results could be used to evaluate the degradation in performance of an M-QAM full-duplex system caused by amplifier nonlinearity, and will be helpful in finding the optimal static operating point of an amplifier.

关键词： full-duplex amplifier nonlinear distortion bit error ratio amplitude error phase error

Numerical Simulation of Free Surface by an Area-Preserving Level Set Method

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Communications in Computational Physics 2012年第4期11卷 1347-1371页

作者： Tony W.H.Sheu C.H.Yu Department of Engineering Science and Ocean Engineering National Taiwan UniversityNo.1Sec.4Roosevelt RoadTaipeiTaiwan Taida Institute of Mathematical Sciences(TIMS) National Taiwan University Center for Quantum Science and Engineering(CQSE) National Taiwan University

We apply in this study an area preserving level set method to simulate gas/water interface *** the sake of accuracy,the spatial derivative terms in the equations of motion for an incompressible fluid flow are approximated by the fifthorder accurate upwinding combined compact difference(UCCD)*** scheme development employs two coupled equations to calculate the first-and second-order derivative terms in the momentum *** accurately predicting the level set value,the interface tracking scheme is also developed to minimize phase error of the first-order derivative term shown in the pure advection *** the purpose of retaining the long-term accurate Hamiltonian in the advection equation for the level set function,the time derivative term is discretized by the sixth-order accurate symplectic Runge-Kutta ***,to keep as a distance function for ensuring the front having a finite thickness for all time,the re-initialization equation is *** the verification of the optimized UCCD scheme for the pure advection equation,two benchmark problems have been chosen to investigate in this *** level set method with excellent area conservation property proposed for capturing the interface in incompressible fluid flows is also verified by solving the dam-break,Rayleigh-Taylor instability,two-bubble rising in water,and droplet falling problems.

关键词： Level set method phase error upwinding combined compact scheme Hamiltonian symplectic Runge-Kutta area conservation property

New low noise interface circuit for detecting weak current of micro-sensors

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Journal of Harbin Institute of Technology(New Series) 2011年第4期18卷 9-12页

作者：谭晓昀孙明王佳琪尹亮刘晓为 MEMS Centre Harbin Institute of Technology Key Laboratory of Micro-Systems and Micro-Structures Manufacturing Ministry of Education Δθ is the error phase-transformationcaused by the charge amplifier Bruun E. "CMOS current conveyors"in Circuits and Sys-tems Tutorials. New York: IEEE Press 1996. 632 - 640..12.New low noise interface circuit for detecting weak current of micro-sensors

A new low noise interface circuit for detecting weak current of micro-sensors is *** using the transimpedance amplifier to substitute the charge amplifier,the closed-loop circuit can avoid the phase error of the charge ***,the phase compensation devices will be cancelled,because there is no phase transformation through the transimpedance *** well as,by using CCCII devices to implement the high value feedback resistor of the impedance amplifier,the noise of the I-V transformation devices is reduced,comparing with the passive *** floating resistor is easy to be integrated into chips,making the integration of the interface circuit of the intelligent sensors *** the simulation,the phase error of the charge amplifier is almost 9°at 2 kHz and it changes with the working frequency of the micro-sensors making the phase compensation not *** value of the floating resistor is 250 kΩ where the bias current is 50 μ*** noise of the active resistor is 0.037 fV2/Hz,comparing with the noise of the passive resistor,which is 4.14 fV2/Hz.

关键词： micro-sensor weak signal detection phase error low noise

An improved method for phasing crystal structures with low non-crystallographic symmetry using cryo-electron microscopy data

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Protein & Cell 2015年第12期6卷 919-923页

作者： Jia Wang (1) (2) (3) Weiguang Wang (1) (2) Wen Song (2) (3) (4) Zhifu Han (2) (3) (4) Heqiao Zhang (2) (3) (4) Jijie Chai (2) (3) (4) Hongwei Wang (2) (3) (4) Jiawei Wang (1) (2) 1.State Key Laboratory of Membrane Biology School of Life Sciences Tsinghua University Beijing 100084 China 2.Center for Structural Biology School of Life Sciences Tsinghua University Beijing 100084 China 3.Tsinghua-Peking Center for Life Sciences School of Life Sciences Tsinghua University Beijing 100084 China 4.Ministry of Education Key Laboratory of Protein Science School of Life Sciences Tsinghua University Beijing 100084 China

Cryo-electron microscopy （cryo-EM） and macromolecular crystallography （MX） both allow the creation of three-dimensional images of biological macromolecules. EM data usually provide access to three-dimensional reconstructions of large biological complexes at low resolution, whereas MX usually delivers atomic or quasi-atomic resolution structures （1-3 A）.

关键词： phase error Molecular Replacement Histogram Match TLR13 Molecule Solvent Flatten

Influence of cryogenic permanent magnet undulator motion error on magnetic field error and radiation intensity loss

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Radiation Detection Technology and Methods 2018年第1期2卷 200-206页

作者： Shu-Chen Sun Wei-Fan Sheng Hui-Hua Lu Xiao-Yu Li Shu-Tao Zhao Ling-Ling Gong Wan Chen Zhi-Qiang Li Lei Zhang Yu-Feng Yang Xiang-Zhen Zhang Ya-Jun Sun Laboratory of Particle Acceleration Physics&Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Science Beijing 100049China

A cryogenic permanent magnet undulator prototype designed for Chinese High Energy Photon Source Test Facility(HEPSTF)at Institute of High Energy Physics is constructed and now *** precision of girders is a significant parameter to guarantee gap error so as to avoid phase error and radiation intensity *** order to study and minimize girder parallelism errors,RADIA and SPECTRA are used to calculate qualified motion *** Modules and single motor closed-loop feedback are designed to compensate the *** field is finally tuned to reach *** of the study and analysis will be presented in this paper.

关键词： Motion precision test Cryogenic permanent magnet undulator phase error Radiation intensity