闪电VHF辐射相位干涉测向系统的数字化实现

VHF相位干涉仪在辐射信号探测方面有着广泛地应用,介绍了基于FPGA的VHF相位干涉测向系统,用于高速闪电波形数据的采集与测向,本系统采用数字复解调技术取代传统的模拟方式实现的VHF相位干涉仪,极大提高了系统的运算精度和抗噪声性能,并且可以实时改变接收频点。详细讨论了数字复解调技术的原理以及在FPGA上的实现,最后给出了测试结果,验证了系统的性能。     

多通道宽带数字接收机的设计与实现

宽带数字接收机主要应用于软件无线电的实现和电子战中。本文介绍了多通道宽带数字接收机的主要用途,详细阐述了该接收机的设计原理和硬件架构,并为实际工程需要设计了算法和程序,对多路输入信号进行了测试,试验表明该接收机性能可以满足实际工程需要。     

配电网宽带数字通信设备研制

提出了一种基于OFDM技术的配电网宽带数字通信设备研制方案，详细地分析了系统中每一个关键功能模块实现方法，讨论了利用DSP和FPGA技术实现的核心功能模块，例如，IFFT／FFT，同步电路、自适应均衡电路、抗配电网输电线上突发干扰的纠错方法等。     

数字示波器宽带探头系统的校准研究

微波射频芯片进行时域测量时,数字示波器的宽带探头是测试芯片的一个关键子系统,为准确测量芯片,必须要清楚示波器探头系统的传输性能。为此,设计了一种包含接地共面波导的数字示波器宽带探头校准系统,依据校准系统的信号传输特性,用反卷积求出数字示波器宽带探头系统的频率响应,并计算其带宽,以实现对该探头系统的校准。之后用该方法对Keysight Infiniimax高频差分有源探头系统进行了校准,得到其带宽数值约为12 GHz与标称带宽12 GHz相符,表明设计的校准系统合理可行。     

浅淡电力系统宽带数字通信网的建设

从节点设备和通道建设等方面讨论了如何组建经济、适用的电力系统宽带数字通信网。     

A new sparse design framework for broadband power amplifier behavioral modeling and digital predistortion

In this paper, we propose a new sparse framework for the design of the behavioral model and digital predistorter of a broadband power amplifier (PA). We start by formulating the Volterra kernel to multidimensional memory polynomial by considering the high‐order dynamic truncation of the Volterra model. Then we show how an estimate of the most significant coefficients may be obtained using a matching pursuit (MPT) algorithm by exploiting the sparsity of the model. After the indices of the nonzero coefficients are roughly estimated, the block exact Householder inverse QR‐decomposition‐based recursive least squares (HIQRD‐RLS) algorithm is utilized to estimate the sparse model complex coefficients. For broadband nonlinear PAs, the proposed approach is demonstrated to achieve the best performance among the well‐known traditional approaches in terms of in‐band and out‐of‐band specifications. The proposed approach is also validated by evaluating the digital predistortion (DPD) performance on a Class‐AB PA in terms of adjacent channel power ratio (ACPR). © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于数字比较法的宽频标准电流互感器溯源技术研究

对于宽频标准电流互感器的校准,在50Hz附近的频段通常采用测差的方法,而在低至5Hz高至2.5kHz的频率下,由于标准器大都采用磁通门传感器的原理,无法与被检互感器的变比一一对应,因此必须采用同步采样的数字比较方法,本文通过对同轴分流器的宽频特性分析,设计了一种适合同轴分流器自校准的宽频互感器校验仪,以此完成对宽频标准电流互感器的误差校准,并采用多功能校准源与高精度数字万用表的配合实现分流器的校准和溯源。文章提供了完善的校准方案和详实的测试数据,并对各环节的校准不确定度进行了科学的分析,论证了校准方法的合理性和准确性,本方法对目前正在运行的浙江省电力公司20Hz示范性电网的计量工作有很大的实用意义。     

PC broadband security

The only real disadvantage to broadband is something generally overlooked by the average Internet user, i.e. security. The always on, high bandwidth, connection that cable modems and DSL lines give their users make them alluring targets for unscrupulous people more so than slow dial-up connections.     

特高频设备的有关故障分析及处理

针对ＷＴＧ１０型特高频设备的实际应用,分析了常见故障,提出了一些基本的解决方法,取得明显效果。     

垂尾隐蔽式超短波全向天线的一体化设计

以单极子天线为研究对象,首先对传统单极子天线的工作原理进行了分析,并研究了不同情况对天线性能的影响,然后在此基础上提出了一种新型结构的平面单极子天线,它选用三角形的结构,并采取了加载元件、提升馈电点等技术,有效地减小了平面单极子天线的结构和尺寸,与此同时,有效地实现了天线带宽的展宽,并且在设计中采用了加载技术,实现天线性能的进一步优化.在理论分析的基础上,使用电磁场仿真软件HFSS对天线进行了仿真分析,通过参数扫描得到了天线的最佳尺寸,并分析了天线的方向图和增益等特性.然后对3种不同情况下的天线进行仿真与分析,分别是无限大地平面、有限大地平面、加入钉子和灯泡的复杂结构后,并优化其参数使其获得最佳的特性.最后根据以上仿真结果,提出了复杂结构垂尾隐蔽式超短波天线的一体化设计的方法.并进行了综合仿真,实现了在100～400 M的频段内驻波比小于2.75.     

船舶自动识别系统（AIS）VHF接收机的设计

VHF接收机是船载自动识别系统(AIS)的关键部件之一,其性能直接影响到AIS系统自组织组网的优劣、接收船舶的数目多少及所能接收到最远船只的距离远近。本文根据国际海事组织(IMO)有关标准,给出了一种船舶自动识别系统中VHF接收机的设计方案。文中简介了接收机的工作原理,给出了基于MAX2306的VHF接收机的硬件和软件设计。实验测试和实际应用表明该接收机的接收灵敏度、邻信道选择性等都已达到规定的要求,并且该接收机结构简单、性能稳定,易于批量化生产。     

True broadband multimedia experience

Even though the fourth-generation (4G) wireless story has not yet been defined, it is clear that the industry is moving aggressively to a 4G world. The pace of 4G adoption as well as the rate at which standards are being developed is by far the fastest of all previous generations of wireless. Whereas it took nearly ten years for third-generation (3G) to roll out and become standardized, 4G activities are proceeding on a much faster three-year cycle.     

基于甚高频的语音增强算法研究

甚高频通信在民航中有广泛应用,但是它极易受到各种噪声的干扰,传统方法去噪效果差且没有消除固有干扰,提出了一种基于小波分析的自适应卡尔曼滤波算法.该算法在小波分析中提出了新阈值函数,在自适应卡尔曼滤波算法中增加了调节窗口长度的自适应因子,以此来调节滤波增益,可以有效地避免滤波发散.随机选择了某一时段4种不同频率的甚高频语...     

In-line Sagnac interferometer current sensor

The authors demonstrate for the first time a near shot noise limited in-line Sagnac interferometer current sensor. It is shown to have a number of advantages over the optical current sensors based on polarimetric Faraday and Faraday/Sagnac loop interferometer topologies, including lower sensitivity to environmental disturbances, less demanding optical components, and easy installation. Its application to power system measurements is also detailed     

Inertial measurement using atom interferometer

The recent advances of atom interferometer and its application in precision inertial measurement are reviewed. The principle, characteristics and implementation of atom interferometer are introduced and it can be used to measure gravitational acceleration, gravity gradient and rotation for its high sensitivity. We also present the principle, structure and new progress of gravimeter, gravity gradiometer and gyroscope based on atom interferometer.     

中电飞华PLC宽带运营试验

运营商在PLC产业链中处于关键的位置，PLC产业发展的前提是运营商能够盈利，而规模性运营试验则是一个必不可少的过程。论文介绍了PLC的试验运营情况，分析了运营的盈利问题，并对PLC未来发展的有效途径进行探讨。     

Conical inductors for broadband applications

Inductors are an integral component in radio-frequency (RF) and microwave circuit design and are typically used as either impedance-matching elements or bias chokes. There are a wide variety of inductors designed to meet today's diverse applications. Using an inductor in a given application requires understanding its capabilities and limitations. One of the main limitations of an inductor is its self-resonance frequency or first parallel-resonance frequency (PRF), which affects the usable bandwidth. This application note presents a commercially available, very high performance inductor that can be used for very broadband UHF to millimeter-wave choking or bias feed applications. Conical inductors are capable of extremely broadband, resonance-free inductance in the microhenry range that can be used for low-loss RF choking and bias feeding. The conical shape combined with careful assembly to low capacitance attach pads allows usable bandwidth of these inductors from 10 MHz to 40 GHz. The conical inductor overcomes the limited bandwidth seen in standard SMT inductors by virtue of its conical design and careful assembly.     

并行多通道间谐波宽带测试方法

针对电站等电力场所多点谐波动态检测的难点,提出基于多输入、多输出系统测试方法,对输入、输出频响进行复指数拟合,得到全频段的间谐波参数.该方法在研制的并行测试系统中应用,实现了主、从结构测试与分析系统,主站引擎软件作为主控平台协同控制各从站,实现从站的内部多通道同步、从站之间的脉冲同步和远程GPS同步.测试表明该方法能够...     

地闪放电过程的甚高频辐射特征分析

为了研究闪电的甚高频辐射特征，自行研制了闪电甚高频辐射脉冲探测和定位系统，并将其用于对地闪的280MHz辐射电场进行了观测。研究了4次地闪的甚高频辐射波形及其特征，得出地闪在该频段的辐射可分为3类，孤立脉冲、连续脉冲和多个孤立脉冲，进一步分析给出了这三类辐射脉冲信号在闪电的不同阶段发生的频数和所占的比例，统计分析结果表明在地闪的预击穿过程中孤立脉冲电场波形所占的比例最大，而在梯级先导过程中连续脉冲电场波形所占的比例最大，预击穿过程中的多个孤立脉冲数大于梯级先导中的多个孤立脉冲数，最后对这种现象的产生机制进行了探讨，认为此现象是由于梯级先导的电磁辐射比预击穿过程强而造成的。