数字调谐系统在组合音响上的应用

本文介绍了NEC公司大规模专用集成电路μPD1715G——016及其在组合音响上的应用,讨论了设计中的几点关键性问题,并分析了解决问题的方法和途径。     

视盘机测试盘制作与应用测量

视盘机测试盘制作的好坏与所作的测试盘能否正确和精确地用于测量是直接相关的。根据原电子部电子行业标准计划,1997年三所”研制了VCD视盘机测试盘。根据原电子部［1998」038号文1998年11月至12月底,经过二个月的实际工作,又制作了超级VCD视盘机电性能测试盘。在这些测试盘制作过程中,特别是在超级VCD电性能测试盘制作中,就压缩编码系统的选择、信源及其产生、亮度清晰度测试卡信号的录制。信噪比测试信号的录制和应用测量。350线多波群频率点和Y扫频频标选择等,取得了不少经验和体会。l压缩编码系统的选择超级VCD视盘存储的是…     

失谐对开放的∧型系统无粒子数反转激光增益的影响

本文使用开放型三能级无粒子数反转激光模型,从原子密度算符运动方程出发,讨论了定态情况下驱动场和探测场失谐对激光增益和折射率的影响。理论分析表明：若驱动场Ｒａｂｉ频率较小,只有探测场共振时才能得到最大的增益;调整探测场的失谐可以获得无吸收高折射率;驱动场Ｒａｂｉ频率较大而达到某一阈值后,调整探测场的失谐将出现特别增益区。驱动场失谐的变化对折射率产生的影响比对增益更为显著。以上结论与封闭型三能级无粒子     

基于熵调整模糊c-均值聚类的时频能量混合模型

本文提出了一种改进由时频不相交分量组成信号的双线性时频分布的分辨率和可读性的方法。用修正的Xie-Beni聚类有效性指标对熵调整模糊c-均值聚类算法进行拓展将模糊聚类与密度估计相结合,实现了信号时频分量的识别和建模;信号的时频能量混合模型给出了信号分量的数目及其在时频面上所占据的区域。这些信息可以用于分离信号分量,设计适合于每个分离分量的光滑核。仿真结果表明,对于由时频不相交分量组成的信号,本方法可以识别出其中的信号分量,并得到较优的时频分布。     

用任意阵实现二维到达角和极化的联合估计

基于四阶累积量和ＥＳＰＲＩＴ算法提出一种新的任意高斯噪声环境上多个独立空间信号二维到达角和极化的联合估计方法。该算法的阵列由和坐标轴方向一致的偶极子对组成,各偶极子对的排列结构任意。计算机模拟结果证实了方法的可行性。     

用于软X射线光刻的等离子体源及干涉诊断分析

阐述了等离子体的产生机理和影响软 Ｘ 射线产生的因素,利用产生软 ｘ 射线的实验系统,分析了软ｘ 射线转换效率与原子数的关系及其空间相干性。给出了等离子体的干涉诊断方法及几个重要的结论。     

Design and implementation of a real-time eye tracking system

Driver fatigue severely affects driver's alertness and ability to drive safely. There are vital problems related to drivers fatigue on driving of trains, vehicles and airplanes. Therefore, the driver fatigue research is important. In this paper, we first study the impact of eye locations on face recognition accuracy, with Haar-like feature and AdaBoost classifier, face and eye area can be detected quickly and accurately. In the part of eye tracking, cam-shift based mean-shift algorithm is used to track the eyes. This method could automatically adjust the size of tracking window according to the different posture of driver. The performance of our eye detection method is validated by using image database with more than 6000 pictures. In addition, our real-time eye tracking system has been tested on railway line segment (China). There are 5 train drivers involved in the experiment. The validation shows that our eye detector has an overall 93% eye detection rate.     

Metal Micropatterning by Triboelectric Spark Discharge

Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospheric environment is developed, where a triboelectric nanogenerator (TENG) is employed to precisely and safely control the voltage, current, and frequency of the spark discharges. Micropatterns of metal films like gold, silver, copper, aluminum and platinum are successfully fabricated on substrates of polyimide, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, paper or latex, even on ultrathin substrates (5 μm thick) without damage, where the feature sizes of metal patterns are controllable from 20 μm to 1 mm. Experimental insights into the triboelectric spark discharge behaviors and the pattern feature sizes control are discussed. A straightforward fabrication of metal patterns on the balloon surface or human skin through “handwriting” by a pencil as discharge electrode is realized. Besides metals, extended processibility of conductive materials like carbon nanotubes, graphene, MXene, graphite, carbon fibers, and conductive polymers are also demonstrated. This work proves the possibility of microfabrication by TENG, which is of simplicity and attractiveness for flexible electronics.     

无源雷达中多波束DBF的设计方法

论述了无源雷达中实现多波束数字波束的方法。阐明通道幅相误差的构成,指出幅相一致性对波束形成的影响,提供了校准通道和评估形成波束的实用方法。给出了在Champ-av3主板上实现多波束DBF的硬件框图和软件流程。