Dual channel heterodyne microscope

Heterodyne measurement of the amplitude and phase of a cross‐polarized two‐frequency laser beam reflected from a patterned surface enables simultaneous imaging in both the amplitude and phase‐contrast modes. Such imaging duality provides additional information for inspection. Besides, spatial resolution in the phase‐contrast mode of operation is not limited by the width of the focused beam and, therefore, may be better than that of traditional imaging techniques. This phenomenon, commonly referred to as super‐resolution, was experimentally observed.     

测量精度达3.2nm的在线表面粗糙度外差干涉仪信号处理系统

介绍了用于磨床加工的光外差表面粗糙度在线干涉测量仪整机的信号处理系统,着重讨论了其中的两项关键技术,即利用负反馈构成的宽动态范围测量信号的自动电压控制以及依据计大数和测小数相结合的高精度动态相位测量,系统的测量精度达２．６°（相当于３．２ｎｍ）,允许测量中最大多普勒频移±１０ｋＨｚ（对应高度的变化率±８．７５×１０＾－３ｍ／ｓ）完全满足磨床加工中表面粗糙度在线测量的要求。现场测试证实了这一点,这对     

40 Gb/s 4-QAM OFDM radio over fiber system at 60 GHz employing coherent detection

In this paper, the simulation of 60 GHz millimeter-wave radio over fiber link with 4-QAM OFDM modulation format at 40 Gb/s over 150 km SMF is proposed. The 60 GHz millimeter-wave signal is generated by the optical heterodyne method. Coherent detection has been used at the receiver to down-convert millimeter-wave signal to IF band. Introduction of the OFDM modulation in RoF-based system realizes the benefits of higher order modulations (such as 4-QAM, 16-QAM, etc.) to ensure the good spectral efficiency and multi-gigabit access. The performance of the system is analyzed by Q-factor and BER by which it can be shown that the best results are obtained at the input power of 10 dBm. The simulation results clearly demonstrate the feasibility of this 4-QAM OFDM RoF system over 150 km fiber link.     

载波注入的无传感器PMSM转子自测角研究

提出一种基于载波电压信号注入的新型无传感器永磁电机转子自测角原理,将电机本体作为旋变器,向电机绕组中注入载波电压激励信号．在分析载波电压信号激励下永磁同步电机数学模型的基础上,研究了基于凸极跟踪转子位置的自测角方法．讨论了载波信号的注入、提取以及包含转子位置信息的高频负序电流的外差处理技术．采用仿真结果进行了分析,通过旋变器的实测结果验证了其正确性．仿真结果表明,以此机理实现的永磁同步电机无传感器控制具有很好的鲁棒性,同时具有良好的静、动态性能．     

Spatial Fourier spectroscopy

A brief analytic survey of the early studies devoted to the development of a spatial analog of Fourier spectroscopy and its principal advantage, the extension of the range of application to the study of high-speed processes, is given. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 22–26, April, 2008.     

高速回转机械扭转振动测量的研究

讨论了高速大型回转机械扭转振动测量的特点及其对测量系统的要求，针对这些要求，提出一种新型激光多普勒扭转振动测量方法。     

Dual-channel heterodyne microscope: new functions

Quantitative assessment of critical dimensions of sub-wavelength structures, dark-field and bright-field modes of operation, recognition of nonpatterned anisotropic surfaces, and three-dimensional profiling of opaque and transparent samples are the new features of a super-resolution dual-channel heterodyne microscope that was introduced in a previous publication in this journal. The aforementioned modes of operation can be activated by simple rotation of a polarizer or insertion of a polarization-separating prism. Various experimental results are presented, demonstrating new performance capabilities of the heterodyne microscope.     

一种频率可调的光学生成微波毫米波源

实现了一种频率可调的光纤微波毫米波信号源.利用掺饵光纤(EDF)环形腔中的偏振烧孔(PHB)效应和激光反向传播的特点,在室温下得到了波长间隔可调的稳定的单频单纵模双波长激光器,将两束激光在PIN光电二极管中拍频得到了频率在472.5MHz~26.5GHz间变化的毫米波信号,输出功率不小于0.015mW,3dB带宽约为3...