Simulation of dual transponder carrier ranging measurements

The most dominant error source for microwave ranging is the frequency instability of the oscillator that generates the carrier phase signal. The oscillator noise is very difficult to filter due to its extremely low frequency. A dual transponder carrier ranging method can effectively minimize the oscillator noise by combing the reference phase and the to-and-fro measurement phase from the same single oscillator. This method does not require an accurate time tagging system, since it extracts phases on the same satellite. This paper analyzes the dual transponder carrier ranging system by simulation of the phase measurements with comprehensive error models. Both frequency domain and time domain noise transfer characteristics were simulated to compare them with dual one-way ranging. The simulation results in the two domains conformed to each other and demonstrated that a high level of accuracy can also be achieved by use of the dual transponder carder ranging system, with relatively simple instruments.     

旋转矢量法在"简谐振动"教学中的应用

“简谐振动”是普通物理力学中的一个基本和重要内容，借助于旋转矢量法，便于学生理解简谐振动的相位和初相位两个物理量的意义，对理解“简谐振动”的有关概念和规律有很大帮助，因谐振子的运动是变速直线运动，而用此方法因为旋转矢量A的转动是匀速的，所以求“简谐振动”的质点运动的时间间隔变得简单，为“简谐振动”的叠加提供了简明的方法。     

集成运放的最小相位误差组合应用技术

针对减小集成运放相位误差的传统方法,指出传统方法的局限性.引入单片集成匹配双运放、三运放组合的思想,形成有源反馈补偿的最小相移方法,分别从电路设计、数学推导、实际参数比较及计算,详细讨论集成运放的最小相位误差组合应用技术,在指定相位误差下,可有效扩展频带.这对相位误差有着严格要求的电路与系统有着重要意义.     

基于全相位FFT的高精度频率计设计

给出了频率计硬件系统和软件系统的设计方案,又对实验结果进行了详细的分析,最终验证设计达到了预期的目标,得到一个精度高、体积小,能够迅速准确地测量低频和高频的频率计。     

基于三维重建的分布式卫星SAR干涉测高模型及误差分析

基于InSAR目标三维重建原理对分布式卫星SAR干涉测高系统模型及工作原理进行了分析,给出了完整的目标位置三维重建闭合形式解;并对影响三维重建精度的主要误差源——基线矢量误差和干涉相位误差进行了详细分析;最后通过仿真分析了基线矢量误差和干涉相位误差特性,从而为系统参量定标及其校正提供了基础.     

阵列天线微波成像多通道相位误差校正方法

采用阵列天线的微波成像系统会产生多通道幅相不一致性问题.针对使用阵列天线进行微波成像的应用,将回波模型中的多通道相位误差分为距离偏移误差和残余常数相位误差,并分析其对成像造成的影响,研究了使用回波中选定参考点目标进行相位误差校正的方法.最后通过微波成像国家重点实验室开发的地基实验系统数据验证了我们的分析和结论.     

Integrated phase unwrapping algorithm for the measurement of 3D shapes by Fourier transform profilometry

An integrated and reliable phase unwrapping algorithm is proposed based on residues and blocking-lines detection, closed contour extraction and quality map ordering for the measurement of 3D shapes by Fourier-transform profilometry （FTP）. The proposed algorithm first detects the residues on the wrapped phase image, applies wavelet analysis to generate the blocking- lines that can just connect the residues of opposite polarity, then carries out the morphology operation to extract the closed contour of the shape, and finally uses the modulation intensity information and the Laplacian of Gaussian operation of the wrapped phase image as the quality map. The unwrapping process is completed from a region of high reliability to that of low reliability and the blocking-lines can prevent the phase error propagation effectively. Furthermore, by using the extracted closed contour to exclude the invalid areas from the phase unwrapping process, the algorithm becomes more efficient. The experiment shows the effectiveness of the new algorithm.     

In-vivo retinal imaging by optical coherence tomography using an RSOD-based phase modulator

Fourier-domain rapid scanning optical delay line （RSOD） was introduced for phase modulation and depth scanning in a time-domain optical coherence tomography （TD-OCT） system. Investigation of parameter optimization of RSOD was conducted. Experiments for RSOD characterization at different parameters of the groove pitch, focal length, galvomirror size, etc. were performed. By implementing the optimized RSOD in our established TD-OCT system with a broadband light source centered at 840 nm with 50 nm bandwidth, in vivo retina imaging of a rabbit was presented, demonstrating the feasibility of high-quality TD-OCT imaging using an RSOD-based phase modulator.     

平衡仪在离心式转机上的应用及注意事项

转机动平衡问题一直是困扰我厂机组稳定运行的大问题,尤其是引风机和排粉机,严重的影响了机组负荷,通过对不同找动平衡方法的学习、总结,我们找到了一些减少叶轮磨损的方法,也总结了一些使用平衡仪应注意的事项并取得经验值,在排粉机上进行应用取得了很好的效果,现将此经验推广到更多的离心式转机上,希望为电力安全产做出更大的服务。     

Dyn11联接组变压器并联时反相序的解决方案

萨拉齐电厂1 #机组照明变和2 #机组照明变并联前的核相工作中,发现相序错接的情况.此类问题经常出现在电厂的调试过程中,本文详细分析了Dyn11联接组别的变压器在并联时,高压侧反相序造成核相结果异常的原因,以及确定解决核相结果异常的两种方案.