超宽带脉冲波形的收发特性分析

采用时域电场积分方程和互易原理相结合的方法,探讨了已知接收信号的情况下,脉冲发送信号的波形,并研究了视距和非视距两种传播路径对脉冲收发信号的影响.在分析中,脉冲波形和天线几何形状可以任意.分别以蝴蝶形天线和超宽带槽式天线为例,并将计算结果与已知接收脉冲信号进行了比较.它们之间良好的一致性说明了所提方法的正确性和有效性.     

一种语音同步提示的倒车雷达的设计

主要阐述倒车雷达的原理,设计方法和电路组成。本设计可实现语音信息的同步播放,为驾驶员提供更加便捷的报警提示,采用的探测方式是超声波测距,处理器采用AT89C2051高速单片机。     

High power impulse magnetron sputtered p-type γ-titanium monoxide films: Effects of substrate bias and post-annealing on microstructure characteristics and optoelectrical properties

In view of wide potential use as p-type oxide semiconductor of titanium monoxide (TiO), it is deposited in this work by using high power impulse magnetron sputtering (HIPIMS), which is known to provide less hysteresis effect in reactive sputtering and better control in stoichiometry. A strong correlation among the preparation parameters on the microstructure and optoelectrical characteristics of the obtained Ti-O films are investigated.Experimental results show that the crystallinic cubic γ-TiO can be directly grown on unheated glass substrate. In regard to the effects of substrate bias and post-annealing, the as-grown γ-TiO transfers into rutile (R-TiO₂) at a critical substrate bias voltage of −125 V or post-annealing temperature of 500 °C. For the purpose of p-type channel layer in transistor, the optimum γ-TiO film exhibiting a high hole mobility of 8.2 cm²/V s is grown at the substrate bias voltage of −25 V and followed by the post-annealing at 400 °C.     

Robustness of SDOF elastoplastic structure subjected to double-impulse input under simultaneous uncertainties of yield deformation and stiffness

A series of impulse-type inputs has been extensively used to evaluate the critical response of an elastoplastic structure subjected to diverse types of pulse-type inputs, including a near-fault ground motion. In this paper, we consider the critical double-impulse input for a single-degree-of-freedom elastic–perfectly plastic structure, and study effects of structural uncertainties. When the natural frequency (or, equivalently, the stiffness) is fixed, the critical response of the structure does not necessarily decrease as the yield deformation (or, equivalently, the yield force) increases. As the first contribution, we give through investigation of this non-monotonicity property. Moreover, we present a systematic method for finding the worst-case scenario when the yield deformation and the stiffness of a structure assumed to be uncertain simultaneously. Numerical examples are presented to illustrate that the robustness of a structure does not necessarily improve when the yield deformation and/or the yield force is increased.     

闪光灯电容器老练工艺的研究

介绍了对闪光灯电容器在不同条件下进行老练工艺试验的结果，选择了合适的温度和电压条件，并采用时间间隙老练工艺，取得了满意的结果。     

基于功率合成的超宽带冲击雷达研究

用电路合成和空间合成技术，将多个数干伏、纳秒级、超宽带脉冲源合成为兆瓦级高功率脉冲源；文中设计了一套由功率合成的全固态脉冲发射机、超宽带平面喇叭收发天线阵、正交解调采样接收机、主控计算机四大部分组成的冲击体制雷达目标探测系统，介绍了系统的工作原理；给出了实际系统目标探测的外场试验相关试验结果，验证了系统的可行性以及信号处理算法的正确性和有效性，为高功率冲击体制雷达技术的发展奠定了一定的实践基础。     

超宽带技术概述

介绍了无线通信领域的新技术超宽带无线电（UWB）的技术优点和调制方式，并将UWB与其他短距离无线通信进行了对比，最后简单分析了UWB在下一代无线通信中的应用前景。     

准分离或伴音系统和BTSC电视多路伴音接收机设计与实践

电视拦收机为获得高质量的立体声和双伴音,必须设法降低系统动态噪声和内载波蜂音。本文在分析了现行电视机中产生内载波蜂音的原因之后,介绍了准分离式伴音系统原理和应用单片Zenith-dbx解码集成电路设计的BTSC制式电视多路伴音接收机。     

用光声效应产生声拍

报道了用光声效应产生各种不同频率的声波，并用这些声波相干叠加产生声拍的实验原理，方法和实验结果。     

超宽带无线通信技术

超宽带(UWB)具有传输速率高、通信距离短、平均发射功率低等特点,非常适合于短距离高速无线通信.文章对UWB的发送接收技术和信道建模方式进行了讨论,指出UWB将定位于各种消费类电子设备和终端间的高速无线连接.对于IEEE的UWB标准,文章认为由于目前形成了脉冲无线电和多频带正交频分复用(OFDM)两大方案,因此最终采用哪种方案还需等待.