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ached)andon-timecontrolproblems;severitygreaterrisk,accordingtotherequiredtroubleshooting,registrationform,andsignedbythoseresponsibleforthesecurityoftheunitforthefirstafterescalation.Thirdarticleopenminemanageroncoalmineproductionjobdistrictwithinofsecurityhiddentroubleshooting,andgovernanceandreportfullisresponsiblefor;securityDeputyManagertieManagerwork,theparagraphconstructionteamheadandthebusinessdepartmentheadMember,andrunmaintenancepersonnel,areshouldaccordingtotheirofdutiesrange,onproductionequipment,andfacilities,andsiteenvironment,aspectsofsecurityhiddenforcheckandreport,andbyhiddenrectificationprogrammeforhiddengovernance.Fourthopen-pitminesafetysectionisresponsibleforthesupervisionandinspectionintheproductionareatroubleshooting,managementandreportingofcomprehensivework.Articlescopeandfocusoftheinspectionpersonnelatvariouslevels:1,operatingpersonnelbeforetakingoverandshiftbeforethejurisdictionareatoconductacomprehensiveinspectionofequipment,runningthesquadleaX大学考试试题纸( A 卷) 课程名称高频电子线路A 题号 一 二 三 四 五 六 专业班级通信、电信0601-06、SY 七 八 九 十 总分 题分 10 10 10 10 10 15 10 10 15 100 备注: 学生不得在试题纸上答题(含填空题、选择题等客观题) 一、(10分,每小题1分) 单项选择题 1、常用集电极电流流通角?的大小来划分功放的工作类别,丙类功放 。 A) ? = 180O B) 90O? ??180O C) ? =90 O D) ??90O 2、在模拟乘法器上接入调制信号VΩmcosΩt和载波信号Vcmcosωct后将产生 。 A)ωc±Ω B)2ωc±Ω C)2ωc D)频谱分量 3、放大器工作在欠压状态,随着负载谐振电阻RP的增大而向临界状态过渡时, 放大器的交流输出电压Vcm将 。 A) 减小 B) 增大 C) 略有增大 D) 略有减小 4、设石英振荡器的振荡频率介于串联谐振频率与并联谐振频率之间时,石英晶体的 。 A) 等效阻抗为0 B) 等效阻抗无穷大 C) 等效阻抗成感性 D) 等效阻抗成容性 5、谐振功率放大器工作于欠压区,若集电极电源VBB中混入50Hz市电干扰,当输入为等幅正弦波时,其输出电压将成为 。 A) 调频波 B) 等幅正弦波 C) 直流信号按50Hz正弦变化的波 D) 调幅波 6、多级单调谐小信号放大器级联,将使( )。 A)总增益减小,总通频带增大 B)总增益增大,总通频带减小 C)总增益增大,总通频带增大 D)总增益减小,总通频带减小 7、SSB信号的检波可采用( )。 A)小信号检波 B)大信号检波 C)同步检波 D)以上三种均可 8、 调幅、检波和混频电路的实质都是( )。 A)频谱的非线性搬移 B)频谱的线性搬移 C)相位变换 D) 以上三种均可 erondutyduringmajorequipmentoverhaul,beforeandaftertheshifttodesignatedstafftounderstandtheoperationofequipmentintheequipmentandcheckonfocus.2,equipmentrepairequipmenttoselectmaintenancecheckatleasttwiceaweektokeyequipmentanddefectivedevicestoincreasethefrequencyofinspection.Teamleaderdedicatedtothedeviceeverydayoperationofalldeviceswithinthescopeofmaintenancepersonnelunderstandthemaintenanceandinspectionofkeyequipment.Paragraph3,theownerandprofessionalandtechnicalpersonnelshouldbecarriedoutdailyafterworksitevisitinspection...Evening.Controlroom:focusedoncoalseamspontaneouscombustionundertroubleshooting,help,landslide,coalfire,earth-moving,roadcarwallsitesafetysupervision,andconscientiouslyimplementtheminerectificationmeasures.Productiontechnologysection:isresponsiblefortroubleshootingwhetherexistsSupercapacity,andSuperached)andon-timecontrolproblems;severitygreaterrisk,accordingtotherequiredtroubleshooting,registrationform,andsignedbythoseresponsibleforthesecurityoftheunitforthefirstafterescalation.Thirdarticleopenminemanageroncoalmineproductionjobdistrictwithinofsecurityhiddentroubleshooting,andgovernanceandreportfullisresponsiblefor;securityDeputyManagertieManagerwork,theparagraphconstructionteamheadandthebusinessdepartmentheadMember,andrunmaintenancepersonnel,areshouldaccordingtotheirofdutiesrange,onproductionequipment,andfacilities,andsiteenvironment,aspectsofsecurityhiddenforcheckandreport,andbyhiddenrectificationprogrammeforhiddengovernance.Fourthopen-pitminesafetysectionisresponsibleforthesupervisionandinspectionintheproductionareatroubleshooting,managementandreportingofcomprehensivework.Articlescopeandfocusoftheinspectionpersonnelatvariouslevels:1,operatingpersonnelbeforetakingoverandshiftbeforethejurisdictionareatoconductacomprehensiveinspectionofequipment,runningthesquadlea9、调幅接收机采用AFC电路的作用( )。 A) 稳定中频输出 B) 稳定输出电压 C) 稳定VCO D) 改善解调质量 10、不具有压电效应的滤波器是 。 A) 石英晶体滤波器 B) LC滤波器 C) 陶瓷滤波器 D) 声表面波滤波器 二、(10分,每小题1分)判断题 1、LC并谐振电路谐振时,感抗与容抗都为零,所以回路呈纯电阻特性。( ) 2、采用倍频器,可以降低发射机主振器的频率,有利于稳频、提高发射机的工作稳定性和扩展发射机的波段。( ) 3、传输线变压器与普通变压器传递能量的方式是不同的。( ) 4、锁相环路就是通过输出信号相位跟踪输入信号相位,最终使两者相位差锁定为零。( ) 5、电容三点式振荡电路输出的谐波成分比电感三点式的大,因此波形较差。( ) 6、集总参数指元件参量与流经它的电流或加于其上的电压的数值无关。( ) 7、调频波的调频指数与调制信号幅度成正比,与调制信号频率成反比。( ) 8、某谐振放大器工作在过压状态,现要调整使之工作到临界状态,若其他参数不变,可以增加负载Re来实现。( ) 9、克拉泼振荡电路比考毕兹振荡电路的频率稳定度高,是因为克拉泼电路的振荡回路中接入一个电容C3,从而能减小晶体管输入、输出电容对振荡回路的影响。( ) 10、单边带通信之所以得到广泛的应用,是因为它与普通调幅波相比大大节省了能量,而且占据频带压缩了。( ) 三、(10分,每小题1分) 填空题 1、集电极调幅,应使被调放大器工作于_______状态。 2、LC串联谐振回路 下降,频带变宽,选择性变差。 3、调相时, 与调制信号幅度成正比。 4、谐振功率放大器的 是当VCC、VBB、Vbm等维持不变时,电流、电压、功率和效率等随电阻Rp的增加而变化的特性。
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erondutyduringmajorequipmentoverhaul,beforeandaftertheshifttodesignatedstafftounderstandtheoperationofequipmentintheequipmentandcheckonfocus.2,equipmentrepairequipmenttoselectmaintenancecheckatleasttwiceaweektokeyequipmentanddefectivedevicestoincreasethefrequencyofinspection.Teamleaderdedicatedtothedeviceeverydayoperationofalldeviceswithinthescopeofmaintenancepersonnelunderstandthemaintenanceandinspectionofkeyequipment.Paragraph3,theownerandprofessionalandtechnicalpersonnelshouldbecarriedoutdailyafterworksitevisitinspection...Evening.Controlroom:focusedoncoalseamspontaneouscombustionundertroubleshooting,help,landslide,coalfire,earth-moving,roadcarwallsitesafetysupervision,andconscientiouslyimplementtheminerectificationmeasures.Productiontechnologysection:isresponsiblefortroubleshootingwhetherexistsSupercapacity,andSuperached)andon-timecontrolproblems;severitygreaterrisk,accordingtotherequiredtroubleshooting,registrationform,andsignedbythoseresponsibleforthesecurityoftheunitforthefirstafterescalation.Thirdarticleopenminemanageroncoalmineproductionjobdistrictwithinofsecurityhiddentroubleshooting,andgovernanceandreportfullisresponsiblefor;securityDeputyManagertieManagerwork,theparagraphconstructionteamheadandthebusinessdepartmentheadMember,andrunmaintenancepersonnel,areshouldaccordingtotheirofdutiesrange,onproductionequipment,andfacilities,andsiteenvironment,aspectsofsecurityhiddenforcheckandreport,andbyhiddenrectificationprogrammeforhiddengovernance.Fourthopen-pitminesafetysectionisresponsibleforthesupervisionandinspectionintheproductionareatroubleshooting,managementandreportingofcomprehensivework.Articlescopeandfocusoftheinspectionpersonnelatvariouslevels:1,operatingpersonnelbeforetakingoverandshiftbeforethejurisdictionareatoconductacomprehensiveinspectionofequipment,runningthesquadlea5、预加重是在发射机的调制器前,有目的地改变调制信号,使其高频端得到加强,以提高调制频率高端的 。 6、超外差接收机中,中频频率为465KHZ,当接收信号载频为 KHz时,本振频率为1000KHz。 7、矩形系数Kr0.1定义为单位谐振曲线N(f)值下降到 时的频带范围与通频带之比。 8、锁相环路的组成是鉴相器、环路滤波器和 。 9、RC相移振荡器中放大器应采用反相放大器;至少要________节基本RC相移网络。 10、放大器的设计是要在满足 和选择性的前提下尽可能提高电压增益。 四、(10分,每小题5分)简答题 1、引起高频小信号放大器工作不稳定的原因是什么?用什么办法克服? 2、二极管大信号峰值包络检波器的非线性失真有哪些?避免失真的原因及条件是什么? 五、(10分) 指出下图所示振荡器的名称,推导其振荡频率的表达式,并说明电路的特点。
(C1、C2<< C4, C1、C2>>C3 ) 六、(15分,每小题5分)画图题 1、 画出斜率鉴频器的电路原理图。 2、 画出直接脉冲计数式鉴频的电路原理框图。 3、 分别画出单一频率的调制信号进行幅度调制,当调幅指数大于1、等于1和小于1时的调幅波形图,同时画出调制信号和载波信号波形。
erondutyduringmajorequipmentoverhaul,beforeandaftertheshifttodesignatedstafftounderstandtheoperationofequipmentintheequipmentandcheckonfocus.2,equipmentrepairequipmenttoselectmaintenancecheckatleasttwiceaweektokeyequipmentanddefectivedevicestoincreasethefrequencyofinspection.Teamleaderdedicatedtothedeviceeverydayoperationofalldeviceswithinthescopeofmaintenancepersonnelunderstandthemaintenanceandinspectionofkeyequipment.Paragraph3,theownerandprofessionalandtechnicalpersonnelshouldbecarriedoutdailyafterworksitevisitinspection...Evening.Controlroom:focusedoncoalseamspontaneouscombustionundertroubleshooting,help,landslide,coalfire,earth-moving,roadcarwallsitesafetysupervision,andconscientiouslyimplementtheminerectificationmeasures.Productiontechnologysection:isresponsiblefortroubleshootingwhetherexistsSupercapacity,andSuper3