斜率鉴频器

2016~2017学年第二学期《高频电子线路》课程设计报告题目：斜率鉴频电路的设计专业：班级：姓名：指导教师：电气工程学院2017年5月21日一、任务书课题名称斜率鉴频电路的设计指导教师（职称）周珍艮(副教授）执行时间2016~2017学年第2学期第13周设计目的1.培养学生团队合作精神2.可很好地理解《通信电子线路》课程中所涉及到的基本内容、基本概念、基本电路结构与原理、基本分析方法与简单的计算方法。3.培养学生设计通信电子线路和解决实际问题的能力。4.使学生基本学会一种优秀的电子电路仿真软件。设计要求5.原理分析及电路图设计6.用相关仿真软件画出电路并对电路进行分析与测试7.（1）输入信号不大于1V，负载电阻300欧，输出信号大于3V（2）中心频率大于1MHz（3）频偏小于50KHz摘要通过研究鉴频器是输出电压和输入信号频率相对应的电路。按用途可分为两类。第一类用于调频信号的解调。常见的有斜率鉴频器、相位鉴频器、比例鉴频器等，对这类电路的要求主要是非线性失真小，噪声门限低。第二类用于频率误差测量，如用在自动频率控制环路中产生误差信号的鉴频器。对这类电路的零点漂移限制较严，对非线性失真和噪声门限则要求不高。斜率鉴频器是晶体管和LC回路实质上是一个调谐放大器，但回路的谐振频率f0与已调频信号的中心频率fc是失谐的。一旦已调频信号的瞬时频率发生变化,放大器就输出一个与之相对应的调幅-调频波。经二极管检波处理，即可在负载RL上得到与原调制信号变化规律相同的输出。斜率鉴频器的电路比较简单，但回路失谐时其谐振特性曲线不是直线，因而鉴频特性的线性较差。通过研究斜率鉴频电路了解了信号的调制和解调，有关未来斜率鉴频电路的微型化研究奠定了一定的基础。关键词：鉴频器;输入信号;二极管检波.Bystudyingthefrequencydiscriminatorcircuitoutputvoltageandtheinputsignalcorrespondingtothefrequency.Accordingtousecanbedividedintotwocategories.ThefirstcategoryforthedemodulationofFMsignal.Aslopediscriminatoriscommon,phasediscriminator,ratiodetector,forthistypeofcircuitismainlyrequirednonlineardistortion,second.Lownoisethresholdforfrequencymeasurementerror,asusedintheautomaticfrequencycontroldiscriminatorgeneratesanerrorsignalintheloop.Thiskindofzerodriftofthecircuitisstrictlylimitedtothenonlineardistortionandnoisethresholdisnothigh.AslopediscriminatorisatransistorandLCcircuitisessentiallyatunedamplifier,butthecenterfrequencyofFCresonantfrequencyf0circuitandhasFMsignalisdetuning.OncetheinstantaneousfrequencyoftheFMsignalamplifieroutputchanges,acorrespondingamplitudemodulationandfrequencymodulationwave.Throughthediodedetectorprocessing,outputcanbeobtainedwiththesamemodulationsignalchangesintheloadontheRLcircuit.Aslopediscriminatorcircuitisrelativelysimple,butwhenthedetuningresonancecharacteristiccurveisnotastraightline,sothelinearfrequencyispoor.Bystudyingtheslopefrequencydiscriminationcircuit,themodulationanddemodulationofthesignalareunderstood,whichlaysafoundationforthefutureresearchoftheslopefrequencydiscriminationcircuit目录第一章鉴频器介绍....................................................................................................................11.1鉴频器............................................................................................................................11.2鉴频器原理...................................................................................................................11.3鉴频特性（曲线）.....................................................................................................21.4鉴频器的主要参数......................................................................................................21.4.1鉴频器的中心频率0f..............................................................................21.4.2鉴频带宽Bm.....................................................................................................21.4.3鉴频器的线性度..............................................................................................21.4.4鉴频跨导DS......................................................................................................21.5鉴频方法.......................................................................................................................31.5.1直接鉴频法.......................................................................................................31.5.2间接鉴频法......................................................................................................3第二章斜率鉴频器电路及原理.............................................................................................42.1单失谐回路斜率鉴频器.............................................................................................42.2双失谐回路斜率鉴频器.............................................................................................52.3差分峰值斜率鉴频器..................................................................................................7第三章电路的分析和原理......................................................................................................93.1鉴频电路的分析...........................................................................................................93.2二极管包络检波器的原理分析...........................................................................10第四章电路的仿真及结果....................................................................................................124.1Multisim仿真软件介绍.......................................................................................124.2电路的仿真电路图及结果.....................................................................................124.3仿真分析.....................................................................................................................14第五章总结................................................................................................................................15参考文献......................................................................................................................................16附录..........................................................................................................................................