浅析音频器件的交流参数测试

音频器件在我们的日常生活中随处可见,这类器件在集成电路中占的比例也不小。如何保证器件的质量是测试工程师的一项重要任务。简单介绍几类音频类的放大器及他们的工作原理,阐述如何对器件中的交流电参数在各种测试平台上进行快速有效的测试。     

浅析音频器件的交流参数测试

音频器件在我们的日常生活中随处可见,这类器件在集成电路中占的比例也不小。如何保证器件的质量是测试工程师的一项重要任务。简单介绍几类音频类的放大器及他们的工作原理,阐述如何对器件中的交流电参数在各种测试平台上进行快速有效的测试.     

音频传输线的测试与分析（下）

音频传输线的测试与分析（下）耿纯通过以上的实践，对音频传输线的各种传输特性进行了一点探讨。下面，就列举一些具体的实例。荷兰范登豪公司是世界上对于音频传输线的研制与生产最领先的厂家之一。该厂生产的包银信号线、包金信号线和非金属线（碳纤维线），在音频信号...     

WCDMA手机射频杂散测试不确定度浅析

本文针对利用手机综合测试仪E5515C和频谱分析仪E4440A组成的WCDMA手机射频测试系统在测试杂散过程中容易引入的测试不确定度进行了分析计算。     

音频功放产品的安规测试和认证

0引言随着音乐会、演唱会日益增多,音频功放产品也层出不穷。生产符合国家安规标准要求的音频功放产品成为广大制造厂商共同关心的事情。根据近几年安规测试、认证过程中经常遇到的问题,结合GB8898-2001深入解读,探讨相应的解决方法。     

基于可用性测试的手机图形用户界面设计

采用"手提式实验室"的测试方法、以与GUI密切相关任务条的形式对某款手机进行可用性用户测试,数据记录和分析,用户交流,然后结合设计艺术学科的经典原理,针对手机GUI设计,初步提出了界面设计在一致性、可视性、视效风格、效率、出错、满意度方面的启发性原则.     

Android手机应用界面布局的可用性测试研究

目的研究手机应用中标签与操作按钮的布局关系。方法对不同品牌的Android手机和其他系统手机的应用界面布局进行比较分析,并在此基础上总结和设计出了3款界面布局方案。结论通过可用性测试,考察这些设计方案是否符合用户的期望和使用习惯,了解用户对不同设计方案的满意度。     

浅谈手机软件测试

随着手机的普及,手机已经成为手机消费的主力,不管是诺基亚、苹果,还是塞班、安卓系统,任何一款手机的使用都离不开手机软件,而在手机软件的开发当中软件测试无疑是一个重要的环节。本文根据已有的研究资料,详细了解手机软件测试的目的作用,就测试的流程开展详细的探讨,希望通过研究提高手机软件的开发水平,为手机用户的使用提供更好的软件服务,方便用户的生活。     

音频工作站录制电平标准的探讨

在刚建立起来的音频系统中,由于数字、模拟设备的混和使用经常会出现不同部门之间、台内和台外制作设备的音频电平不统一的现象,导致节目播出出现时大时小的现象,较大影响播出效果。这种情况在GY/T192-2003《数字音频设备的满度电平》中有解释：“在广播电视音频系统中（包括节目的制作、播出及传输）,在混合使用数字和模拟设备时,如果数字音频设备的满度电平值选择不恰当,     

Toxicity characterization of waste mobile phone plastics

Waste plastic housing units (N=60) of mobile phones (of different models, and brands), were collected and analyzed for lead, cadmium, nickel and silver using atomic absorption spectrophotometry after acid digestion using a 1:1 mixture of H2SO4 and HNO3. The mean (+/-S.D.) and range of the results are 58.3+/-50.4mg/kg (5.0-340mg/kg) for Pb, 69.9+/-145mg/kg (4.6-1005mg/kg) for Cd, 432+/-1905mg/kg (5.0-11,000mg/kg) for Ni, and 403+/-1888mg/kg (5.0-12,500mg/kg) for Ag. Approximately 90% of the results for the various metals were < or =100mg/kg. Results greater than 300mg/kg were generally less than 7% for each metal and could be attributed to exogenous contamination of the samples. These results suggest that there may not be any immediate danger from end-of-life (EoL) mobile phone plastic housing if appropriately treated/managed. However, considering the large quantities generated and the present low-end management practices in most developing countries, such as open burning, there appears a genuine concern over the potential for environmental pollution and toxicity to man and the ecology.     

揭秘手机“监听卡”骗局

想监听老公(老婆)在你背后做什么?手机监听卡帮您圆梦。您是否收到过类似的短信呢?所谓的监听卡真的能监听到吗?记者以客户的身份了解到,货倒是可以货到付款,但是卡不能直接用,必须在交上钱以后,才能告诉你密码。看不到发荣誉证书的单位记者首先联系到的是一家华阳商务软件调查有限公司,网页上有产品介绍、功能说明、使用说明和产品价格等内容,其中在功能说明中介绍,     

Tracking employment shocks using mobile phone data

Can data from mobile phones be used to observe economic shocks and their consequences at multiple scales? Here we present novel methods to detect mass layoffs, identify individuals affected by them and predict changes in aggregate unemployment rates using call detail records (CDRs) from mobile phones. Using the closure of a large manufacturing plant as a case study, we first describe a structural break model to correctly detect the date of a mass layoff and estimate its size. We then use a Bayesian classification model to identify affected individuals by observing changes in calling behaviour following the plant''s closure. For these affected individuals, we observe significant declines in social behaviour and mobility following job loss. Using the features identified at the micro level, we show that the same changes in these calling behaviours, aggregated at the regional level, can improve forecasts of macro unemployment rates. These methods and results highlight promise of new data resources to measure microeconomic behaviour and improve estimates of critical economic indicators.     

Radio characteristics evaluation tests of an experimental 3G WCDMA system in Taiwan suburban environments

Abstract

An experimental study on the radio characteristics of a 3G WCDMA system in a Taiwan suburban environment was conducted. This paper presents the results of handover behaviors. The examinations and performance evaluation are based on the measured E_b /I ₀, mobile system transmitting power, bit‐error‐rate and frame‐error‐rate statistic distributions with respect to the time variations, which corresponds to different measurement locations, under individual and independent but appropriate design of experiment procedures. The corresponding radio characteristics are analyzed and evaluated according to the measured data.     

Recall of past use of mobile phone handsets

Previous studies investigating health effects of mobile phones have based their estimation of exposure on self-reported levels of phone use. This UK validation study assesses the accuracy of reported voice calls made from mobile handsets. Data collected by postal questionnaire from 93 volunteers was compared to records obtained prospectively over 6 months from four network operators. Agreement was measured for outgoing calls using the kappa statistic, log-linear modelling, Spearman correlation coefficient and graphical methods. Agreement for number of calls gained moderate classification (kappa = 0.39) with better agreement for duration (kappa = 0.50). Log-linear modelling produced similar results. The Spearman correlation coefficient was 0.48 for number of calls and 0.60 for duration. Graphical agreement methods demonstrated patterns of over-reporting call numbers (by a factor of 1.7) and duration (by a factor of 2.8). These results suggest that self-reported mobile phone use may not fully represent patterns of actual use. This has implications for calculating exposures from questionnaire data.     

3GPP LTE接入网体系结构与空中接口协议

3GPPLTE(Long Term Evolution)项目是3G标准的演进,它改进并增强了3G的空中接入技术,采用OFDM,MIMO、全IP组网等先进的无线通信技术。本文介绍了LTE的演进目标,分析了LTE系统结构。     

Tolerance optimization of a mobile phone camera lens system

In the manufacturing process for the lens system of a mobile phone camera, various types of assembly and manufacturing tolerances, such as tilt and decenter, should be appropriately allocated. Because these tolerances affect manufacturing cost and the expected optical performance, it is necessary to choose a systematic design methodology for determining optimal tolerances. In order to determine the tolerances that minimize production cost while satisfying the reliability constraints on important optical performance indices, we propose a tolerance design procedure for a lens system. A tolerance analysis is carried out using Latin hypercube sampling for evaluating the expected optical performance. The tolerance optimization is carried out using a function-based sequential approximate optimization technique that can reduce the computational burden and smooth numerical noise occurring in the optimization process. Using the proposed design approach, the optimal production cost was decreased by 28.3% compared to the initial cost while satisfying all the constraints on the expected optical performance. We believe that the tolerance analysis and design procedure presented in this study can be applied to the tolerance optimization of other systems.     

WCDMA空中接口RLC层的AM传输方式关键技术的研究

以WCDMA标准为依据,简要介绍了该标准空中接口方案的无线链路控制子层（RLC层）,并对RLC层确认数据传输方式中发送／接收缓冲区的设置以及状态报告的形成进行了深入探讨。     

Driver hand-held mobile phone use and safety belt use

The purposes of the study were to identify hand-held mobile phone use trends for Michigan and to compare safety belt use between users and nonusers. Mobile phone and safety belt use was investigated by a direct observation survey of drivers at intersections in Michigan. Data were weighted to calculate mobile phone use and safety belt use rates statewide. The study showed 2.7% of Michigan drivers were using a mobile phone at any given daylight time. Safety belt use of current mobile phone users was significantly lower than those not using mobile phones.     

安全RFID与NFC手机的互动防伪应用

随着射频识别技术（RFID）技术的发展与成熟,RFID技术其远距离识别、存储量大、标签唯一编码标识、环境适应性强等技术优势,逐步在溯源防伪领域取得了应用和推广。伴随移动互联网的高速发展,智能手机已经逐步成为人们接触外界信息的最主要设备,被称为个人感官的延伸。将NFC智能手机与RFID技术结合,应用于溯源防伪领域,具备很好的应用前景。