朗讯cdma 1x基站分组管宽度的配置

简单介绍朗讯系统cdma 1x基站分组管(PP)宽度的配置，并对朗讯cdma 1x基站分组管宽度不合理的配置及信道板扩容后的PP宽度配置进行了案例分析。     

用WinDriver工具包开发设备驱动程序

针对Windows9x/NT及Windows2000操作系统,利用WinDriver工具包开发了PCI插卡设备驱动程序,保证程序在不同的操作系统下有良好的移植性和兼容性。还结合PCI桥芯片S5933开发了数据采集卡设备驱动程序。     

非制冷红外探测器用VO_x薄膜的制备

介绍了一种采用反应溅射工艺 ,通过控制不同气氛的分布制备VOx 薄膜的方法 ,并制备出电阻温度系数 (TCR)优于 - 2 %的非制冷红外探测器用VOx 薄膜。其XPS、XRD分析结果表明 ,薄膜的生长情况与制备工艺条件有密切关系。     

基于LPC2138的AES3数字音频接口设计

随着数字音频技术的不断发展,数字化音频设备已广泛应用于广播电视节目领域。鉴于专业数字音频设备越来越多地需求,以及专用接收发送设备的复杂性,本设计采用Philips公司的ARM7控制芯片LPC2138结合音响设备专用芯片,设计一个简单的AES/EBU(AES3)数字音频收发系统,实现了专业AES3数字音频的接收与发送。实验显示,在输入1 kHz,24 dBu时,本设计的总谐波失真小于0.005%,信噪比大于90 dBu。     

一种多脉冲激励线性预测声码器的仿真实现

本文是笔者所开发的语音信号处理课程中的一个研究型实验教学案例.文中概述了多脉冲激励线性预测声器的编码方法,并用MATLAB做了仿真实现.在本声码器实现方法中,在发送端对系统参数进行量化时,用量化LPC滤波器的PARCOR系数（部分相关系数,PARt CORrelation）代替传统的对滤波器的线性预测系数的量化;在接收端,将PARCOR系数用文中所给的算法转换为线性滤波器的线性预测系数,进行系统重构合成语音,大大降低了传输比特率,并且提高了合成语音质量.     

X‐Region: A framework for location privacy preservation in mobile peer‐to‐peer networks

While enjoying various LBS (location‐based services), users also face the threats of location privacy disclosure. This is because even if the communications between users and LBS providers can be encrypted and anonymized, the sensitive information inside LBS queries may disclose the exact location or even the identity of a user. The existing research on location privacy preservation in mobile peer‐to‐peer (P2P) networks assumed that users trust each other and directly share location information with each other. Nonetheless, this assumption is not practical for most of the mobile P2P scenarios, for example, an adversary can pretend to be a normal user and collect the locations of other users. Aiming at this issue, this paper presents x‐region as a solution to preserve the location privacy in a mobile P2P environment where no trust relationships are assumed amongst mobile users. The main idea is to allow users to share a blurred region known as x‐region instead of their exact locations so that one cannot distinguish any user from others inside the region. We propose a theoretical metric for measuring the anonymity property of x‐region, together with three algorithms for generating an x‐region, namely, benchmark algorithm, weighted expanding algorithm, and aggressive weighted expanding algorithm. These algorithms achieve the anonymity and QoS requirements with different strategies. Our experiments verify the performance of the algorithms against three key metrics. Copyright © 2013 John Wiley & Sons, Ltd.     

Hollow Multishelled Structure of Heterogeneous Co3O4–CeO2−x Nanocomposite for CO Catalytic Oxidation

Herein, hollow multishelled structure (HoMS) of Co₃O₄–CeO_2?x nanocomposites with controllable molar ratio of Co and Ce elements is synthesized by a general strategy sequential templating approach (STA) with a facile and efficient electrostatic spray process. As a catalyst of carbon monoxide (CO) catalytic oxidation, Co₃O₄–CeO_2?x (Co/Ce = 4/1) HoMS achieves good catalytic activity (complete conversion temperature is 166.9 °C) and stability (100 h). This performance is attributed to synergistic effects between the two components. The combination of Co₃O₄ and CeO₂ not only generates more interfaces of Co₃O₄–CeO_2?x, which is more favorable for the activation of oxygen, but also improves the oxidizability of Co₃O₄ as well as the capacity of oxygen storage of CeO₂. In addition, the relatively larger effective specific surface area of the HoMS can provide more active sites, while the unique structure of HoMS can facilitate gas diffusion and maintain structural stability.     

CDMA 1x EV-DO覆盖模型的分析与仿真

结合经过校正后的适合于本地无线环境的OKUMURA-HATA传播模型，建立起一种新的本地化基于1x EV—DO系统数据业务吞吐量分析的覆盖预测仿真模型，可应用于1xEV—DO系统的网络规划及系统性能分析。     

一种基于视频会议系统的回声消除算法

回声是影响视频会议系统性能的主要因素之一。本文分析了在视频会议系统中声学回声的形成原理,并介绍了几种主流的回声消除算法。文章分析了各算法的不足,并提出了一种新的回声消除算法,实验证明本文提出的算法是可行的,并且能够达到较好的回声消除效果。     

Hybrid Catalyst Coupling Zn Single Atoms and CuNx Clusters for Synergetic Catalytic Reduction of CO2

Reverse water-gas shift (RWGS) reaction is the initial and necessary step of CO₂ hydrogenation to high value-added products, and regulating the selectivity of CO is still a fundamental challenge. In the present study, an efficient catalyst (CuZnN_x@C-N) composed by Zn single atoms and Cu clusters stabilized by nitrogen sites is reported. It contains saturated four-coordinate Zn-N₄ sites and low valence CuN_x clusters. Monodisperse Zn induces the aggregation of pyridinic N to form Zn-N₄ and N₄ structures, which show strong Lewis basicity and has strong adsorption for *CO₂ and *COOH intermediates, but weak adsorption for *CO, thus greatly improves the CO₂ conversion and CO selectivity. The catalyst calcined at 700 °C exhibits the highest CO₂ conversion of 43.6% under atmospheric pressure, which is 18.33 times of Cu-ZnO and close to the thermodynamic equilibrium conversion rate (49.9%) of CO₂. In the catalytic process, CuN_x not only adsorbs and activates H₂, but also cooperates with the adjacent Zn-N₄ and N₄ structures to jointly activate CO₂ molecules and further promotes the hydrogenation of CO₂. This synergistic mechanism will provide new insights for developing efficient hydrogenation catalysts.