高压隔离驱动器HT04应用

ＨＴ０４为高压隔离驱动器，无需外接电源就可以把ＴＴＬ／ＣＭＯＳ控制信号转换成最高可达４００Ｖ的ＭＯＳＦＥＴ控制信号。本文简要介绍了ＨＴ０４的主要特点，详细介绍了ＨＴ０４在高端开关、恒阻开关、电流控制、背影驱动器、高压选择开关、数据检测系统、固态继电器、汽车控制以及电动机驱动器等方面的实用电路。     

一种基于FPGA和光纤的远端监控模块的设计

为了能够进行实时控制和监听远程设备的故障、状态,设计了一种利用FPGA和光纤通信技术的监控系统。文章采用XC5VFX70T作为核心处理芯片可以方便、灵活处理外部各种接口,控制信号的传输采用自定义的光纤传输协议,协议中增加CRC校验和错误重传保证了控制的准确无误,而状态信号和视频监控信号的传输则利用设计帧结构、时分复用的方法回传。仿真结果表明我们的传输协议是可以实现的。     

基于DDS的超声换能器频率跟踪系统

设计并实现了一种超声换能器频率跟踪系统.该系统采用直接数字合成器(DDS)作为频率调整和信号产生的器件;采用可编程逻辑器件(CPLD)完成相位比较和DDS控制,频率跟踪的响应速度快;单片机作为系统的控制核心,对反馈电流进行实时监控,并在此基础上实现了先扫频后跟踪的策略以及自动解锁控制,使系统有良好的适应性和可靠性.该系统已在超声换能器的实用产品样机上应用,取得了良好的效果.     

卫星广播电视网络监控系统的模型设计

在广播电视系统的监控中,不仅包含了通用监控系统中的常见设备监控,还包括了大量的信号监控,对二者监测和实施控制的准确、高效,是广播电视监控系统成败的关键,也是整个广播电视系统追求的目标。本文主要从监控目标出发,通过分析各监控设备、信号等诸多因素,从而建立一个完整的监控系统模型,并以该模型为核心,以卫星地球站广播电视监控系统为背景,讨论监控系统设计中的关键技术。     

一种高速数据采集／重放系统的实现

介绍了一种高速数据采集／重放系统。该系统采用工业控制计算机作为主控设备，在主控计算机内部配置了大容量内存作为高速海量存储介质。系统采用一块基于FPGA的高速信号采集／回放PCI卡来实现。该卡以FPGA为采集／回放的核心控制芯片，并在FPGA内部实现了64位/33MHz的PCI接口逻辑。系统有实时和非实时两种模式，其采集／回放速度高达240MHz，存储容量能扩展至3GB，它可供电磁信号环境仿真及复杂信号分析用。     

基于ZigBee的电源监控系统设计与实现

针对电源监控功耗过大,精度不高的问题,提出一种基于ZigBee的电源监控系统设计方法。首先进行电源监控系统的整体结构设计,设计主控芯片及外围电路;然后进行电源监控系统的硬件模块化设计,主要包括传感器模块、ZigBee核心控制模块、主控电路、复位电路、同步时钟设计和信号调理电路设计等。采用ARM Cortex-M0处理器内核实现电源监控系统集成设计;最后进行系统的电路调试测试分析,测试结果表明,采用该设计系统具有较高的电源监控调理性能,功耗较小,输出功率增益较大,具有较高的控制品质。     

基于GPRS的油烟远程无线监控系统设计

利用GPRS实现了油烟的远程无线监控.监控系统以AVR单片机为控制核心,通过采集油烟气体传感器TGS2100的信号,并由GPRS和Internet发送到监控中心服务端PC机,从而实现传感器信号的远程实时检测;监控中心发送的控制命令通过无线网络由单片机接收并根据信号控制外部设备,从而实现无线控制.与传统监控方式相比,该系统具有耗资小,使用便利等优点,具有广阔的应用前景.     

简易单片机频率计数器

频率计数器是一种测量信号频率的仪器,在教学、科研、高精度仪器测量、工业控制等领域都有较广泛的应用。频率测量对生产过程监控有很重要的作用,可以发现系统运行中的异常情况,以便迅速做出处理。传统的频率计通常是由简单的组合逻辑和时序逻辑电路作为信号处理系统的控制核心,存在结构复杂、稳定性差、精度不高的弊端,采用测频率法直接测频率,测量的精度相对较低。     

可寻址路权管理和有线电视网络监控

本分析了一种用于可寻址有线电视收费系统的新型无源高频开关技术，同时提出了一种有效的有线电视路权管理和网络监控系统。该系统采用无源高频开关对信号进行关断实现路权控制；利用在电视信号中播中经过加密的节目标为监控对外部恶意信号的侵入，信号的回传方式支持HFC回传信道，无线回传信道，电话回传。它充分利用了计算机技术，网络技术和通信技术，能有效地监控网络的使用状况，使有线电视网络收费，网络管理监控变得更加容易，该系统成本低，安装和使用方便，安全性和可靠性高，为有线电视网络管理工作提出了一种可行的方案。     

一种基于nRF905的微型无线图像传输系统设计

本文介绍了一种微小型的无线图像传输系统方案的设计与实现，详细介绍了系统硬件模块，以及各个模块之间的接口设计。本系统采用微型CMOS图像传感芯片进行图像采集，采用ARM作为控制缓冲器，nRF905负责对图像信号的发送与接收。该系统具有体积小、功耗低、传输速率高等优点，可广泛应用于监控系统以及微型飞行器等领域。     

基于HART-HT2012的数字传感器的设计与开发

HART是高速可寻址远程传感器数据通路。介绍HART MODEM HT2012和智能数字传感器接口模块ADIB60的结构特性,研究了基于HART HT2012的数字传感变送器的系统构成,设计了AT89C51与HT2012和ADIB60的硬件接口以及HT2012与传输介质的接口,给出了系统软件以及数据通信的程序设计。由HT2012与单片机AT89C51和ADIB60组成的数字传感变送器,实现了远程点对点的数据采集和传输,可应用于遥测遥控领域。     

Performance improvement of low bandgap polymer bulk heterojunction solar cells by incorporating P3HT

This work demonstrates a significant improvement of device performance by incorporating the polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) into a low bandgap polymer poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta [2,1-b:3,4-b′]dithiophene-siloe 2,6-diyl]] (Si-PCPDTBT) and [6,6]-phenyl C71 butyric acid methyl ester (PC₇₁BM) host system, to form a ternary blend bulk heterojunction solar cell. The P3HT concentration was varied from 1 to 5 wt% in the host system. P3HT functions as a morphology control agent in this ternary system. A small weight percentage of P3HT can enhance the light absorption, polymer phase separation, exciton separation and charge carrier mobilities. These results are supported by UV–vis spectroscopy, X-ray diffraction, photoluminescence analysis and other characterisation methods. The highest average power conversion efficiency improvement of 10% was achieved by adding 1 wt% P3HT to the host system. This study reveals a promising way to achieve high efficiency solar cells using a low bandgap polymer.     

基于SPCE061A的超低功耗电子温度计设计

系统选用静态功耗2μW的SPCE061A单片机作为主控单元,低功耗温度传感器DS18820采集温度,时钟芯片DS1302提供时间,HT1621D驱动玻璃片实现时间的显示。且系统具有温度控制功能,短时间内可将温度稳定在设定值。系统可通过串口与PC通信,由可视化界面显示温度随时间的变化,形象直观。整机系统可根据需要一键唤醒或进入静态。系统实现了温度时间的显示,测试结果表明：分辨率、功耗、显示和温度控制均达到设计要求。     

Controlled Fabrication of PbS Quantum‐Dot/Carbon‐Nanotube Nanoarchitecture and its Significant Contribution to Near‐Infrared Photon‐to‐Current Conversion

A solution‐processed nanoarchitecture based on PbS quantum dots (QDs) and multi‐walled carbon nanotubes (MWCNTs) is synthesized by simply mixing the pre‐synthesized high‐quality PbS QDs and oleylamine (OLA) pre‐functionalized MWCNTs. Pre‐functionalization of MWCNTs with OLA is crucial for the attachment of PbS QDs and the coverage of QDs on the surface of MWCNTs can be tuned by varying the ratio of PbS QDs to MWCNTs. The apparent photoluminescence (steady‐state emission and fluorescence lifetime) “quenching” effect indicates efficient charge transfer from photo‐excited PbS QDs to MWCNTs. The as‐synthesized PbS‐QD/MWCNT nanoarchitecture is further incorporated into a hole‐conducting polymer poly(3‐hexylthiophene)‐(P3HT), forming the P3HT:PbS‐QD/MWCNT nanohybrid, in which the PbS QDs act as a light harvester for absorbing irradiation over a wide wavelength range of the solar spectrum up to near infrared (NIR, ≈1430 nm) range; whereas, the one‐dimensional MWCNTs and P3HT are used to collect and transport photoexcited electrons and holes to the cathode and anode, respectively. Even without performing the often required “ligand exchange” to remove the long‐chained OLA ligands, the built nanohybrid photovoltaic (PV) device exhibits a largely enhanced power conversion efficiency (PCE) of 3.03% as compared to 2.57% for the standard bulk hetero‐junction PV cell made with P3HT and [6,6]‐Phenyl‐C₆₁‐Butyric Acid Methyl Ester (PCBM) mixtures. The improved performance of P3HT:PbS‐QD/MWCNT nanohybrid PV device is attributed to the significantly extended absorption up to NIR by PbS QDs as well as the effectively enhanced charge separation and transportation due to the integrated MWCNTs and P3HT. Our research results suggest that properly integrating QDs, MWCNTs, and polymers into nanohybrid structures is a promising approach for the development of highly efficient PV devices.     

A thermodynamic and kinetic description of PCBM phase segregation and aggregation in P3HT:PCBM blends

The kinetics and thermodynamics of PCBM phase segregation and aggregation in P3HT:PCBM blends has been studied. We develop a thermodynamic model for PCBM phase segregation in P3HT:PCBM blends which explains the formation of nanoscale crystallites which subsequently diffuse and coalesce into larger PCBM aggregates. We show that the formation of nanoscale crystallites during the film making process prevents spinodal decomposition of the P3HT:PCBM blends even at PCBM weight fractions above the spinodal decomposition boundary for the system. Finally, we demonstrate that the observed aggregate morphology can be understood in terms of a kinetic model based on the diffusional flux lines of PCBM crystallite which, in turn, govern the evolution of the macroscopic growth front.     

Decision of mobile devices enabling high throughput and non‐high throughput medium access control of 802.11n based on the consideration of energy efficiency

To be compatible with the legacy 802.11, there are two major medium access control (MAC) behaviors, high throughput (HT) and non‐high throughput (non‐HT), in the 802.11n. In this paper, we analyze and compare the energy efficiencies of different MAC behaviors in 802.11n on the basis of the Bianchi model and our previous works to evaluate the performance of the different MAC behaviors regarding HT and non‐HT. Our studies try to provide the decision for the mobile stations to enable the HT of 802.11n or not based on the consideration of energy efficiency. Studies show that owing to the large power consumption in HT, it is not suitable for limited power devices to carry WWW traffics by multiple‐input multiple‐output transmission because of large overheads of physical layer in the HT mode. However, if large file transmissions by File Transfer Protocol are considered, the energy efficiency in HT MAC can be very high because of the large aggregated frame size. It is especially true when the number of active stations is large because of the decrease in idle listening time by using the techniques applied in HT MAC such as Aggregate MAC Protocol Data Unit and Block‐ACK. These characteristics in the HT mode can overwhelm the larger overheads of physical layer compared with that in the non‐HT mode when large files are needed to be uploaded. Copyright © 2012 John Wiley & Sons, Ltd.     

Hole-injection enhancement of top-emissive polymer light-emitting diodes by P3HT/FNAB modification of Ag anode

Based on the hole-transport characteristic of poly(3-hexylthiophene) (P3HT), self-assembled thin layer of P3HT was employed to modify the Ag anode of a top-emissive polymer light-emitting diodes (T-PLEDs) to enhance the hole-injection from the Ag anode. The experimental results show that introduction of a P3HT thin layer significantly decreases the threshold voltage of a T-PLED. However, only slightly increase of the work function was achieved due to this modification. To increase the work function of the P3HT modified Ag anode (Ag/P3HT), 1-fluoro-2-nitro-4-azidobenzene (FNAB) was introduced into the terminal tail (–C₆H₁₃) of P3HT thin layer, which leads to a work function increment of 0.23 eV and a further enhancement in the hole-injection. The luminous efficiency achieved by this modified anode (Ag/P3HT/FNAB) is about fourfold higher than the efficiency obtained from the base device.     

基于HT47R20A-1无线数字测量的实现

本文介绍了基于HT47R20A-1单片机的无线数字测量的实现,并详细介绍了HT47R20A-1 A转换器、无线传输发射与接收的构成与实现.     

智能来电显示器的设计

利用单片机控制智能来电显示器,显示器利用低功耗,具有振铃检测、载波检测功能,满足Bell202和V2．3标准的CID芯片HT9032C实现接收来电信息,同时可实现液晶显示、E2PROM存储和语音播报电话主叫号码等功能。以SPI串行接口智能显示键盘控制芯片ZLG7289A为核心设计的键盘电路实现查阅、删除信息。实践表明,显示器外围器件少,抗干扰能力强,方便好用。文中详细介绍了系统的硬件设计和软件流程。特别介绍了主叫识别信息的两种格式和通过串口及模拟串口接收来电信息的两种方法。     

用异步收发器HT6720设计RFID系统

HT6720是可在射频识别系统中制作电子标签的专用集成电路，工作频率为13．56MHz，属于中频识别芯片。该芯片内置96bit OPT存储器，且为只读型。由于HT6720所需要的数据载体结构简单，因此，通过HT6720可用极低的成本生产只读标签和设计射频识别系统。