频谱仪测量发射机带外杂散信号的分析

简述了发射机带外杂散信号的定义及带外杂散信号的测量方法。频谱分析仪测量发射机带外杂散信号时会出现许多虚假信号,从而影响了真实的杂散信号的正确测量。从频谱分析仪工作原理入手对其原因进行了定性分析,给出了虚假信号和真实信号的辨别方法,提出了较为先进的正确测量杂散信号的方法。     

辐射杂散发射比对测试分析

随着无线通信技术的不断发展,辐射杂散发射(RSE)测试日益重要,对实验室间测试数据的一致性也有了更高的要求。这也就要求实验室间的比对测试要更加准确可靠,排除不可控因素,比对测试结果的最大影响因素就是比对测试方案的制定。文章结合无线通信产品的RSE测试标准,通过长期测试验证,从RSE比对测试样品的选择、RSE比对测试方法、RSE比对测试结果评估三大方面,详细分析了可能影响RSE比对测试结果的因素,并给出相应的参考意见,在实验室制定比对测试方案中可以起到参考作用。     

CDMA基站杂散发射测试的一些经验

基站的发射机性能是影响移动通信网络的容量和覆盖特性的最主要的因素之一,因此在CDMA设备入网检测中,对这方面的检测向来都非常严格。随着国家对基站发射性能指标的要求不断提高,原有的测试方法和测试仪器都已经无法满足要求。摩托罗拉(中国)电子有限公司《CDMA基站杂散发射测试的一些经验》一文以基站杂散发射测试为例,指出了原有测试方法的不足,介绍了一种科学的测试基站杂散性能的方法,并推荐了具体的测试仪表。对相关测试人员进行更严格和更完善的基站杂散发射机性能检测有一定参考价值。     

浅谈动态范围对杂散发射测试的影响

随着无线电新技术、新业务的广泛应用,无线电台站数量不断增长,电磁环境日益复杂,无线电干扰日益增多。对无线电管理机构而言,要有效维护空中电波秩序,一方面必须加大无线电监测的力度,及时消除各种无线电干扰;另一方面,必须对各类无线电发射设备严格实施检测,确保其符合国家规定的有关技术标准,从源头消除各类干扰现象的出现。近年来,全国已经有部分省份取得了无线电发射设备型号核准检测和质量认证等资质,检测实验室软硬件设施和技术人员队伍也日趋完善。在实际检测工作中,如何提升设备检测的准确性和检测工作的效率,这对检测人员来说是一个十分重要的课题。笔者认为,要搞好设备检测工作,检测人员必须对实验室所使用的检测设备的各项性能指标了然于胸,这样才能判断实验室的设备是否能够对送检设备进行检测;必须全面了解被测设备的技术特征和工作原理,一旦在检测中出现问题就能及时进行分析和解决;必须全面掌握有关设备检测的具体标准,全面掌握设备检测的目的、检测的条件、检测的原理和测试的方法,从而驾轻就熟地完成检测工作。     

数字集群基站杂散发射测试方法研究及实现

0引言随着无线通信技术的飞速发展,大量通信基站被架设起来以实现个人移动通信。数量众多的无线电台站在占用核定的频率资源同时,由于设备老化等因素,在核定频点之外的频段,会衍生出大量的杂散信号,污染周围的电磁环境,造成无线电频率资源的浪费。     

舰载相控阵天线杂散发射辐射的统计电磁学分析

舰船上的有源相控阵天线各个单元收发组件的杂散发射及其辐射的电磁环境电平是典型的随机量,无法直接 利用适合于确定性问题的计算电磁学方法进行求解。本文建立了舰船环境下相控阵天线的电磁仿真模型,应用电磁场全波分 析结合蒙特卡洛方法的数值统计电磁学方法,分析了舰载相控阵天线杂散干扰的随机特性,给出了相控阵天线杂散发射辐射 的环境电场值随着各个天线单元杂散发射随机特性变化的概率密度统计分布。该方法对于其他随机因素引发的相控阵天线 指标的统计特性分析也具有参考意义。     

CDMA手机传导杂散发射限值的释义及测量

CDMA手机传导杂散发射技术指标在YD/T 1050-2000标准中有明确的规定.理解规定中指标限值的含义是准确测量的前提条件,初次接触测量者易产生概念上的混淆,本文对此加以详细的阐述.     

正交波形MIMO雷达对发射杂散影响的改善

雷达在波形产生和传输过程中会产生杂散信号,这些杂散信号可能干扰雷达检测,产生EMI等。由于正交波形MIMO雷达各个发射通道的发射信号波形是正交的,而某些发射杂散对阵列是不相干的,因此不会产生阵列处理增益,从而就减小了对雷达本身及其他RF系统的干扰。本文分析了雷达发射杂散的信号模型,讨论了发射杂散对正交波形MIMO雷达和传统相控阵雷达的目标检测性能的影响,说明了MIMO雷达在减小杂散影响方面的性能优势。     

调频广播电台杂散发射干扰航空通信典型案例分析

贵州省威宁县毗邻云南、四川，飞往成都、昆明、重庆等方向及过境的各条航线均汇聚于此，形成了空中十字路口，飞机过往频繁。2004年12月，昆明空管中心向我们反映在贵州威宁空管区域地空通信主频率125．75 MHz受到较强的无线电广播干扰，严重影响了过境飞机的安全。接到干扰投诉后，省监测站高度重视，调配两台监测车，组成监测小组赴威宁进行干扰查处。     

CDMA基站杂散发射对GSM基站干扰情况分析

中国联通公司CDMA基站的开通运行近两年来,随着发射设备技术参数的下降等各种原因的出现,它对相邻的中国移动GSM基站的干扰越来越多。笔者在实际工作中发现这类干扰大多数由CDMA基站杂散发射偏大引起。我们先了解GSM基站受干扰时背景噪声电平的大小。根据国家通信行业的标准,GSM基站接收机灵敏度电平Pr′为-104dBm,GSM基站所需的载波干扰比值C/I为9dB。而在实际工作中,由于考虑到环境噪声和多径干扰对基站的影响,我们一般将GSM基站接收机灵敏度电平降低3dB,由此得出GSM基站容许的最大干扰电平I为:I=Pr′+3dBm-C/I=-104dBm+3…     

CDMA与GSM基站共址杂散干扰仿真与分析

随着无线通信技术和服务要求的飞速发展，出现了第二代和第三代系统，以及同一代移动通信系统内不同通信标准共存的情况。中国联通的CDMA系统和GSM系统就是一个最具代表性的例子。不同系统营运于同一个电磁环境下，势必会带来系统之间电磁兼容的问题。对电磁兼容中的共址干扰问题中的杂散干扰做了较深入地探讨。     

A novel out-of-band emission suppression method in future wireless communications employing filtered orthogonal frequency division multiplexing waveform

In order to achieve flexible configuration and asynchronous transmission of different subbands (SBs), SB filters are utilized in filtered orthogonal frequency division multiplexing (f-OFDM) systems to isolate different SBs efficiently. Nevertheless, the price is the insertion of some intrinsic interference.Therefore, the suppression of the out-of-band emission (OOBE) between SBs is essential for the system performance improvement of f-OFDM. According to the system structure of f-OFDM, an optimization design model based on active interference cancelation (AIC) is proposed in this study, and the optimization design model is solved through second order cone programming. Furthermore, the effectiveness of the proposed AIC algorithm in OOBE suppression is verified by computer simulations. To the whole system, the OOBE suppression also means the decrease of inter-SB interference (ITBI). In addition, the influences of main parameters, such as the number of the cancelation carriers (CCs), on the OOBE suppression performance of the proposed AIC algorithm, are simulated and analyzed. Moreover, some intrinsic characteristics of the proposed algorithm in parameter configuration are revealed in terms of power spectral density (PSD) and bit error ratio (BER).     

Hard metallic lens and radome at out-of-band frequencies

The electrical characteristics of a hardenable metallic lens or radome having a near-unity index of refraction are described. The near-unity index of refraction constrains lens designs by either restricting the maximum lens diameter or greatly increasing the focal length. An alternative is to use a metallic grating as a radome, which would retain the hardness properties of the metallic lens. This radome design was experimentally measured at 10 GHz using a parallel-plate grating with spacings between 1 and 4 in. Measured pattern and gain characteristics are reported.     

调频广播电台杂散发射的估测与/A1类航空干扰分析

从近年来的航空干扰投诉中我们发现,航空干扰最为突出的是调频广播台站对航空台站产生的A1类干扰,且最难处理.因为在飞机的航路上,不可避免地会遇上调频广播台站,而调频广播台站的有效发射功率大,一般都在1kW以上,又设于高山高塔上,离飞机航线近,台站长期处于连续发射中,发射机参数发生变化的可能性大,而且都是数台发射机共用一付天线同时发射,对杂散和互调产物的有效抑制比较困难,这些杂散和互调产物会落入机载航空电台引起干扰,从而影响航空导航通信安全,这也就是A1类干扰产生的原因.     

Power penalties due to in-band and out-of-band dispersion in FBG cascades

We measure the in-band dispersion penalty in a cascade of five 50-GHz low-dispersion linear-phase fiber Bragg gratings (FBGs) and compare the results with conventional apodised FBGs. At the 0.5-dB power penalty level, the usable bandwidth of a single linear-phase FBG (40 GHz) is twice as wide as that of a conventional apodised FBG (19 GHz). The bandwidth-utilization factor of a single linear-dispersion grating is 89%, while for the five-grating cascade, it is 76%. To our knowledge, these are the highest values reported to date for cascaded optical devices. The corresponding factors for the conventional gratings are 53% and 31%. We also measure the additional penalty on a dropped channel caused by a cascade of five adjacent-channel gratings. The bandwidth narrowing due to the adjacent-channel FBGs is 6 GHz both for linear-phase and conventional FBGs, giving a usable bandwidth of 34 GHz (linear-phase) and 13 GHz (conventional).     

DDS杂散的抑制与仿真研究

依据直接数字式频率合成器（DDS）的基本工作原理，针对DDS中杂散与噪声的主要来源，综合分析了相位抖动法和延时叠加法的有效性，并运用MATLAB中的simulink建立了DDS仿真模型，通过对仿真结果的研究表明，只有选用合适的相位抖动注入，才能对DDS输出频谱中的杂散分量产生明显的抑制效果。     

The danger of high-frequency spurious effects on wide microstrip line

It has been found that remarkably severe spurious effects can occur in the current excited on microstrip line at moderate to high frequency, when the strip is wide (approximately w/h > 3). This newly observed effect occurs because one or more leaky modes (LMs) approaches the branch point at k/sub 0/ in the complex longitudinal wavenumber plane. When this happens, the attenuation (leakage) constant of these LMs becomes very small. Hence, the LMs can propagate to very large distances along the line with only minimal attenuation. This effect only occurs when the strip is fairly wide, and at certain frequencies. When it occurs, the effect can be disastrous since the continuous-spectrum (radiation) part of the current on the strip then decays very slowly with distance from the source so that the total strip current excited by the source exhibits spurious oscillations out to very large distances from the source. An approximate design rule for predicting this effect is given, which is accurate for wide strips (approximately w/h > 6). The LMs that are responsible for this effect are identified, and the behavior of these modes are studied for different strip widths.     

Recognizing professional distinction [The President's page]

Describes the ComSoc Awards program and lists the winners of the career awards, service awards and best paper awards.     

Design and analysis of a low-noise saw-less receiver front-end resistant to strong out-of-band blocker

Regulatory changes to spectrum management frameworks in the U.S. and worldwide are promoting the use of dynamic spectrum access (DSA) and spectrum sharing mechanisms. Wireless service environments that use these mechanisms will rely heavily on radio interference control and management techniques to coordinate the boundaries of spectrum use for devices owned/managed by different entities. To communicate the characteristics and limits of spectrum use of an RF transmitter, receiver, system or collection of systems, a common data structure to represent this information must be in place. Spectrum consumption models (SCMs) attempt to capture this information and support a set of computations that allow for the determination of the compatibility of the use of spectrum between devices and/or systems that communicate the characteristics of their use of spectrum with these models. SCMs are currently being standardized within the IEEE DySPAN-SC 1900.5.2 workgroup. This paper presents our results and ongoing efforts in developing an open source tool for the construction and analysis of SCMs as a means to promote their use and showcase their potential for enhancing spectrum sharing and DSA interactions.