基于Zigbee的自动校准电子时钟集群控制系统

介绍了一种Zigbee无线通信的自动校准电子时钟集群控制系统。该系统通过物联网Zigbee协议实现自组网络,设定主时钟时间通过上位机网络校准后,通过无线传感网络使其它时钟接受主时钟的信息,并自动修正时间,与主时钟保持一致。下位机采用STM32VC106 ARM微处理器芯片实现电子时钟制作,利用LED显示屏进行时间显示,并可实现网络实时文本信息播报和音频信息播报。     

用广播电台报时信号自动校准电子钟

用音频锁相环NE567组成单音频识别电路，通过软件消除干扰，从广播电台的播音信息中提取出报时信号，作为单片微处理器的中断源，校准电子钟。     

一种新型的音频广播信号压缩方法

本文提出一种新的音频压缩模式,获得了不错的压缩效果。单音频信号失真度测试结果从20Hz到15kHz信号均呈现为较好的正弦波形态;GPS时钟和频率源测试本系统发射信号的频率稳定度达到10-9级别;立体声倒频信号测试、左右声道进行测试均满足要求。数字接口协议确定后即可直接接入同频广播传输系统中,使用方便。本文提出这种新的音频广播压缩的思路以供同行共同探讨其实用可行性。     

用于高性能电流舵型DAC的数字校准模块

提出了一种用于14-bit 400MS/s电流舵型数字模拟转换器的数字校准模块.在校准关闭时,该模块仅作为温度计译码器进行编码转换.在校准开启时,校准开关基于一个低频校准时钟,依次对电流单元进行校准.由于使用单一频率的校准时钟会在SFDR中引入杂散尖峰,降低DAC的动态性能,所以本设计中的数字校准时钟模块采用了LFSR与CA叠加的结构,在频带上提供近似白噪声的输出控制信号.该数字模块采用SMICCMOS 0.18μm 1P6M工艺,电源电压为1.8V.研究结果表明,在200MHz下,对5MHz的输入信号,模块开启后,SFDR的提升接近18dB.可知,该模块可以大幅提高数模转换器的SFDR,可用于高性能电流舵型DAC中.     

浅析出租车计价器故障判断和维修

本文对出租车计价器计价器计价原理和计价系统组成及主要功能进行了分析,对计价器常见故障进行分析并提出解决方法,在出租车计价器计价器检定维修中具有指导意义。     

基于单片机的出租车计价器检定装置的设计

为解决出租车计价器检定装置布线繁琐和检测效率不高的问题, 提出一种以AT89C52单片机为核心的出租车计价器检定装置的设计方法。以霍尔传感器作为检测元件并产生脉冲信号, 通过无线模块将记录的脉冲传送到与微处理器相连的无线接收模块, 并与出租车计价器记录的脉冲个数进行比对, 检测出租车计价器是否符
合计价标准。系统还对检测台的设计进行了改进, 使其在检测过程中更加快捷方便, 提高检测台的使用寿命和检测效率。实验测试结果表明, 该设计符合出租车计价器整车检定装置的技术指标要求, 系统操作方便, 检测精度较高, 稳定性较好, 能满足实际测试的需要。     

一种EPC Gen2 RFID标签时钟校准方法（英文）

设计了一种对Gen2 RFID标签的振荡器产生的时钟信号进行校准的方法,以解决以下问题：因受到工艺偏差的影响,EPC Gen2 RFID标签的振荡器的时钟频率可能与设计时的标称值有偏差,导致标签不能满足协议的要求,或导致标签功耗过大性能下降.该方法设计了时钟校准命令的前导信号,命令代码和命令参数;并给出了读写器使用时钟...     

多功能的出租车计价器的设计与实现

本文介绍了一种以AT89S51单片机为核心的多功能出租车计价器。本计价器不但能实现基本的计价,而且还能根据白天、黑夜、中途等待来调节单价,同时在不计价的时候还能作为时钟为司机同志提供方便,对其硬件实现进行了详细阐述。     

基于音频信号的广告检索和定位

音频信息的检索是多媒体检索技术中的一个重要方面，本文讨论一种基于音频信号的广告条目检索和定位方法，它利用短时平均过零率和互相关函数从实时音频数据流中快速检测和定位广告条目。     

MPEG-Ⅱ实时编码系统中音频编码的实现

基于利用人的听觉心理模型对音频信号进行压缩的管理,描述了MPEG音频压缩标准所采有的MUSICAM算法,并提出了MPEG－Ⅱ实时编码系统中音频编码模块的实现方案,该方案利用手机CPU来完成音频编码的工作,既可充分利用系统资源,又可降低成本,实践表明,该方案满足实时性,稳定性等方面的设计要求。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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