ISO 14443单芯片读卡机解调电路的设计

介绍了ISO 14443标准中IC卡到读卡机通信的信号特征和解调方法,提出了一种新颖的调幅波解调电路的基本原理和电路实现．芯片测试结果显示：电路在2.5～5.5V下都能稳定可靠的工作,工作温度范围为－20～80℃;5V条件下整个解调电路的功耗小于1mA;电路能检测的最小幅度调制信号为5mV．     

ISO 14443单芯片读卡机放大、滤波和量化电路的设计

介绍了ISO 14443解调电路解调后滤波、放大和量化电路的设计,提出了一种新的阈值电压可变的比较器结构.电路经O.6μm工艺生产线流片验证,测试结果显示:电路可在2.5～5.5V电压范围内工作,工作温度为-20～80℃,载波信号衰减大于40dB,电路增益在26～44dB范围内可调,5V条件下,电路的功耗小于10mA.     

ISO 14443单芯片读卡机放大、滤波和量化电路的设计

介绍了ISO 14443解调电路解调后滤波、放大和量化电路的设计,提出了一种新的阈值电压可变的比较器结构. 电路经0.6μm工艺生产线流片验证,测试结果显示：电路可在2.5～5.5V电压范围内工作,工作温度为-20~80℃,载波信号衰减大于40dB,电路增益在26~44dB范围内可调,5V条件下,电路的功耗小于10mA.     

卫星电视接收机的工作原理(8) 音频信号处理电路分析

音频处理电路的作用就是将音频调频信号解调成伴音信号供扬声器发出声音。伴音调频副载波的频率各国标准不同 ,一般都在 4 .5～ 8ＭＨｚ之间 ,我国采用6 .6ＭＨｚ。目前卫星电视接收机中的伴音解调电路都设计为可调谐的 ,能适应各种体制的需要。卫星电视广播的伴音采用模拟信号传输和数字信号传输 2种方式 ,下面分别讨论。1　模拟伴音调频信号的解调模拟伴音调频信号的解调和处理电路方框图如图1所示。图 1　伴音解调和处理电路方框图图像鉴频器输出的视频基带信号经过通带为 4 .5～ 8ＭＨｚ的带通滤波器 ,取出伴音副载波调频信号 ,抑制电视…     

用于RFID标签的自适应低压电流模ASK解调器(英文)

针对RFID标签低压工作的要求,设计了一种自适应电流模ASK解调器.通过把电压信号转换为电流信号、采用两级电流峰值保持技术以及泄漏电路等技术提高了解调器的动态检测性能.解调器的工作电源电压为0.6～1.8 V,能对输入载波幅度为250 mV～1.1 V,调制深度为20%～100%的信号进行正确解调.电源电压为1.8 V时,解调器的动态检测范围从80 nA到3.96μA.电路采用0.18 μm CMOS工艺设计并实现.     

一种带电平转换功能的双电源电压输出电路

出于性能、功耗和兼容性的考虑,芯片的核心电路与I/O电路一般采用不同的电源电压.文中设计了一种新型2.5V/5V双电源电压输出电路,此电路带有新型电平转换电路,能够将摆幅为0～2.5V的内部信号转换为摆幅为0～5V的输出信号.同时,文中所设计的输出电路只使用2.5V耐压的薄栅氧MOS器件,虽然在5V电压下工作,却没有栅氧过压问题.     

基于电流模式的ASK解调器

设计了一种工作在电流模式下的ASK解调器,电路首先将电压信号转换为电流信号,并对电流信号进行延时,然后将延时电流与原始电流进行比较,获取信号的边沿位置,最后用RS触发器还原出最终数据。该解调器可以在一个比较宽的供电电压范围内解调出深度更浅的ASK信号,可以应用到不同标准的RFID标签中,而且电路受工艺变化的影响非常低。电路采用HHNEC 0.35μm5 V CMOS工艺设计,仿真结果表明,供电电压在2.6~5 V之间,在此电压范围内解调器至少可以解调深度为5%的ASK信号。     

一个适用于无线内窥镜系统的ASK中频接收机电路

实现了一个适用于无线内窥镜系统的低功耗ASK中频接收机电路.该接收机包括一个用于补偿信道衰减的自动增益控制环、一个ASK解调器和基于能隙基准源的偏置电路,接收机电路已采用0.25μm CMOS工艺实现.测试结果表明,该电路可以从功率在-30～10dBm之间的中频信号中正确解调出数字基带信号,中频工作频率为20MHz.电路采用2.5V电源,消耗的电流仅为2.1mA.     

一个适用于无线内窥镜系统的ASK中频接收机电路

实现了一个适用于无线内窥镜系统的低功耗ASK中频接收机电路.该接收机包括一个用于补偿信道衰减的自动增益控制环、一个ASK解调器和基于能隙基准源的偏置电路,接收机电路已采用0.25μm CMOS工艺实现.测试结果表明,该电路可以从功率在-30～10dBm之间的中频信号中正确解调出数字基带信号,中频工作频率为20MHz.电路采用2.5V电源,消耗的电流仅为2.1mA.     

ISO15693非接触式IC卡射频前端电路的设计

介绍了ISO15693非接触式IC卡射频前端电路,采用一种巧妙的整流电路,提高了整流效率。同时,使用了一种适用于ISO15693非接触式卡片的简单稳压电路结构,有助于信号的解调,并且使卡片在接收到的信号为10%ASK和100%ASK两种调制模式时都能正常工作。芯片测试结果显示,电源产生电路能够产生一个2.2~3.8 V的直流电压,解调电路能够在2.0~3.8 V电压下可靠稳定地工作;在ISO15693规定的最小场强0.15 A/m处,整个芯片的电源电压为3.3V,且功耗小于60μW。     

Analysis of a strip in a waveguide

An analysis and an experimental study of a strip in a transverse plane of a rectangular waveguide below cutoff are presented. This work is a preliminary step in analyzing a stripline-fed slot antenna array in which each stripline feed is enclosed in a rectangular waveguide below cutoff. A numerical method is developed to solve a “pseudo” mixed-potential integral equation for the current on the strip excited by a delta-gap source at some point along the strip. The Green's function for dipole sources in the rectangular waveguide is used in the spectral and spatial representations and Shanks' transform is employed to speed up the convergence of the doubly infinite series. Numerical and experimental results are presented for a monopole fed at one wall of a rectangular waveguide and for a bottom-fed and bottom-loaded strip in a rectangular waveguide     

一种芯片内部稳压电源的实现

介绍和分析了一种用于PWM控制器内部的稳压电路,采用双极线路结构和4μm工艺。经过PSPICE仿真,它具有0．176mV／V的稳压系数和60dB的纹波抑制比和较低温度系数。     

Design of a mechanism for biaxial rotation of a wing for a hovering vehicle

This paper presents a novel mechanism to actuate the wings of a hovering micro air vehicle (MAV). The mechanism uses a single actuator, but each wing can rotate about two orthogonal axes. The goal of this work is to design a light-weight compact mechanism that flaps the wings, inspired from the wing motion of hummingbird and hovering insects, to generate enough lift for the vehicle to hover. This paper explains in detail the proposed mechanism and its working prototypes. Also, the paper presents a dynamic simulation of the mechanism. The proposed dynamic simulation is used to predict the theoretical lift of the ornithopter. Further, the theoretical model is supported by actual experimental data collected from the prototype. The experimental data shows that the vehicle has the potential to develop enough lift to hover.     

Equivalence of a Nonoriented Line and a Pair of Oriented Lines in a Network

Equivalence of a nonoriented line and a pair of oriented lines (in the reliability-sene) is examined for four types of networks. Type I has one input node and one output node; type II has one input node and two or more output nodes; type II' has two or more input nodes and one input node; type III has two or more input nodes and two or more output nodes. For types I, II, II', every non-oriented line is equivalent to a pair of oriented lines with equal line-reliability. The result corresponds to the presumption that almost every one has taken for granted. However equivalence of such a replacement is not true for a type III network.     

基于智能手机压电基片上微液滴位置分析章

为了降低微流分析成本,该文提出了基于智能手机检测压电基片上目标微液滴方法,并开发出相应的应用软件,通过分析微液滴颜色信息和几何信息定位目标微液滴位置,结合分析时间获取微液滴输运速度。为验证提出方法的正确性,以5 μL黑色墨水溶液微液滴为研究对象,进行压电基片上微液滴识别和位置分析实验。结果表明,该文所提方法和开发的应用软件可识别和定位压电基片上微液滴,在功率为27.5 dBm时,第2~10 s段内微液滴输运速度为0.416 mm/s。     

Analysis of a coaxial-to-waveguide adaptor including a discendedprobe and a tuning post

A field matching analysis of a coaxial-to-waveguide adaptor incorporating a disc-ended probe and a tuning post is presented. In this analysis, the tuning post is considered as a short-circuited second probe. A computer algorithm for calculating the input impedance of this structure is developed. This algorithm is used to investigate and improve the operation of a commercially available coaxial-to-waveguide adaptor     

Transmission-Line Properties of a Strip on a Dielectric Sheet on a Plane

The subject is a strip Iine formed of a strip and a parallel ground plane separated by a dielectric sheet (commonly termed "microstrip"). Building on the author's earlier papers all the significant properties are formulated in explicit form for practical applications. This may mean synthesis and/or analysis. Each formula is a close approximation for all shape ratios, obtained by a gradual transition between theoretical forms for the extremes of narrow and wide strips. The effect of thickness is formulated to a second-order approximation. Then the result is subjected to numerical differentiation for simple evaluation of the magnetic-loss power factor from the skin depth. The transition formulas are tested against derived formulas for overlapping narrow and wide ranges of shape. Some of these formulas are restated from the earlier derivations and others are derived herein. The latter include the second-order approximation for a narrow thin strip, and a close approximation for a narrow or wide square cross section in comparison with a circular cross section. Graphs are given for practical purposes, showing the wave resistance and magnetic loss for a wide range of shape and dielectric. For numerical reading, the formulas are suited for programming on a digital pocket calculator.     

Cancellation performance of a linearisation loop of a feedforwardamplifier

The feedforward linearisation method has the advantage of cancellation performance and linearisation bandwidth over other linearisation approaches. The effects of amplitude imbalance, phase imbalance and delay mismatch on the cancellation performance of a linearisation loop are fully analysed by the authors     

The measurement of a large antenna using a spacecraft as a receiver

Two computational methods for obtaining the gain pattern of a large antenna using power levels recorded by a spacecraft are developed from the transmission equation. Nominally, the large antenna is linearly polarized while the spacecraft's receiving antennas are circularly polarized. Since the spacecraft has no attitude control system, the orientation of the receiving antennas is not known a priori nor its orientation the same from orbit to orbit. The first method relies on an independent spacecraft attitude determination system to furnish the orientation of the receiving antennas. It combines this information with receiving-antenna gain measurements to give the power level of the incident radiation. Losses due to polarization mismatch are taken into account, but polarization loss factors are not actually computed. The second method relates simultaneous measurements made by separate channels with separate receiving antennas. By solving a system of equations numerically, one can determine the direction of the incident radiation as well as its power level. This alleviates the need for an attitude determination system. These methods originated in the operations of the spacecraft NUSAT1 (northern Utah Satellite)