实验2 电容三点式LC振荡器

实验2 电容三点式LC振荡器 guide sex further enhanced, documents handle and running of speed obviously speed up, program gradually specification, conference service and Chief reception of quality and level has has new of improve, Logistics support capability further strengthened. Document management, confidential, confidentiality, duty, letters and other items have been significantly improved. 4, Office construction increased at all levels. City Government offices adhere to strengthen and improve the construction of the system as a breakthrough, has developed a series of code of conduct, continuous improvement of operational mechanism, sound and the implementation of the rules and regulations, and adhere to the system of managing people, according to the rules, the work gradually into the orbit of institutionalization and standardization. Focus on strengthening ideological and political construction of the contingent of cadres, and actively carried out various business training, knowledge of the Office team structure has been optimized, to broaden the range of knowledge and operational capacity grows, nurtured a political firm, sharp, professional and innovative staff, created solidarity, striving for the top, pragmatic, dedication, good image. However, with the State Council and the provincial Government of the national, the province's Secretary-General meeting of government offices under the new situation 实验2 电容三点式LC振荡器 一、实验目的 1(熟悉电子元器件和高频电子线路实验系统; 2(掌握电容三点式LC振荡电路的基本原理，熟悉其各元件功能; 3(熟悉静态工作点、耦合电容、反馈系数、等效Q值对振荡器振荡幅度和频率的影响; 4(熟悉负载变化对振荡器振荡幅度的影响。 二、实验仪器 LC振荡器模块、双踪示波器、万用表 三、实验电路基本原理 1.概述 ,,振荡器实质上是满足振荡条件的正反馈放大器。,,振荡器是指振荡回路是由,,元件组成的。从交流等效电路可知:由,,振荡回路引出三个端子，分别接振荡管的三个电极，而构成反馈式自激振荡器，因而又称为三点式振荡器。如果反馈电压取自分压电感，则称为电感反馈,,振荡器或电感三点式振荡器;如果反馈电压取自分压电容，则称为电容反馈,,振荡器或电容三点式振荡器。 在几种基本高频振荡回路中，电容反馈,,振荡器具有较好的振荡波形和稳定度，电路形式简单，适于在较高的频段工作，尤其是以晶体管极间分布电容构成反馈支路时其振荡频率可高达几百,,,,,,,。 2.,,振荡器的起振条件 一个振荡器能否起振，主要取决于振荡电路自激振荡的两个基本条件，即:振幅起振平衡条件和相位平衡条件。 3.LC振荡器的频率稳定度 频率稳定度表示:在一定时间或一定温度、电压等变化范围内振荡频率的相对变化程度，常用表达式:Δf,f来表示(f为所选择的测试频率;Δf为振荡频率的频率误差，,,,, Δf,f,f;f和f为不同时刻的f)，频率相对变化量越小，表明振荡频率的稳,,,,,,,,,, 定度越高。由于振荡回路的元件是决定频率的主要因素，所以要提高频率稳定度，就要设法提高振荡回路的标准性，除了采用高稳定和高Q值的回路电容和电感外，其振荡管可以guide sex further enhanced, documents handle and running of speed obviously speed up, program gradually specification, conference service and Chief reception of quality and level has has new of improve, Logistics support capability further strengthened. Document management, confidential, confidentiality, duty, letters and other items have been significantly improved. 4, Office construction increased at all levels. City Government offices adhere to strengthen and improve the construction of the system as a breakthrough, has developed a series of code of conduct, continuous improvement of operational mechanism, sound and the implementation of the rules and regulations, and adhere to the system of managing people, according to the rules, the work gradually into the orbit of institutionalization and standardization. Focus on strengthening ideological and political construction of the contingent of cadres, and actively carried out various business training, knowledge of the Office team structure has been optimized, to broaden the range of knowledge and operational capacity grows, nurtured a political firm, sharp, professional and innovative staff, created solidarity, striving for the top, pragmatic, dedication, good image. However, with the State Council and the provincial Government of the national, the province's Secretary-General meeting of government offices under the new situation guide sex further enhanced, documents handle and running of speed obviously speed up, program gradually specification, conference service and Chief reception of quality and level has has new of improve, Logistics support capability further strengthened. Document management, confidential, confidentiality, duty, letters and other items have been significantly improved. 4, Office construction increased at all levels. City Government offices adhere to strengthen and improve the construction of the system as a breakthrough, has developed a series of code of conduct, continuous improvement of operational mechanism, sound and the implementation of the rules and regulations, and adhere to the system of managing people, according to the rules, the work gradually into the orbit of institutionalization and standardization. Focus on strengthening ideological and political construction of the contingent of cadres, and actively carried out various business training, knowledge of the Office team structure has been optimized, to broaden the range of knowledge and operational capacity grows, nurtured a political firm, sharp, professional and innovative staff, created solidarity, striving for the top, pragmatic, dedication, good image. However, with the State Council and the provincial Government of the national, the province's Secretary-General meeting of government offices under the new situation 采用部分接入，以减小晶体管极间电容和分布电容对振荡回路的影响，还可采用负温度系数元件实现温度补偿。 4.LC振荡器的调整和参数选择 以实验采用改进型电容三点振荡电路(西勒电路)为例，交流等效电路如图2-1所示。 C3 BG C1 L C R C2 图2-1 电容三点式LC振荡器交流等效电路 (1)静态工作点的调整 合理选择振荡管的静态工作点，对振荡器工作的稳定性及波形的好坏，有一定的影响，偏置电路一般采用分压式电路。 当振荡器稳定工作时，振荡管工作在非线性状态，通常是依靠晶体管本身的非线性实现稳幅。若选择晶体管进入饱和区来实现稳幅，则将使振荡回路的等效Q值降低，输出波形变差，频率稳定度降低。因此，一般在小功率振荡器中总是使静态工作点远离饱和区，靠近截止区。 (2)振荡频率f的计算 1 f= 2,L(c，c)T 式中C为C、C和C的串联值，因C(300p)>>C(75p),C(1000P)>>C(75p)，故C?C，T1231323T3所以，振荡频率主要由L、C和C决定。 3 (3) 反馈系数F的选择 the functions and priorities compared to the requirements of our gap is still very big. Main is daily in the passive meet of more, active research of less, service also has not timely, and not in place of problem; work in the meet Yu traditional of, and program of of work way, develop innovation spirit and service innovation capacity not strong; supervision information work and promoted decision implementation of contact enough close, feedback situation not active; research resources of using enough full, research results of into degree not high; some sector documents running not specification; Municipal Government Office on the County (district) and municipal government sector Office work of guide enough, No real form interaction and close collaboration, promote the implementation of the work. These problems, we must effectively be addressed in the future work. Second, serve the overall situation, carry out their duties, improve quality, and strive to create a new situation of system of government offices in the city since last season, meeting the Secretary-General of the State Council and the provincial government has held a government system, from a global and strategic height, scientifically analyzed the new situation and the newTasks on the system of government offices bring new situations and new problems and new challenges, profoundly expounded the work of government departments at all levels in the new era should be put in the situation to understand, to grasp, to deploy at any time and under any circumstances, should always focus on the big picture, firmly grasp the overall situation, increasing in the overall implementing in earnest the work of spontaneity, initiative and steadfastness. And explicitly put forward the "surrounding situation, pay attention to implementation" is the core of government offices, requiring government departments at all levels cannot be "Gramophone", "mail room" and "the Messenger" is not confined to paper communications, yinglaisongwang and upload issue. Must to has strongly of implementation guide sex further enhanced, documents handle and running of speed obviously speed up, program gradually specification, conference service and Chief reception of quality and level has has new of improve, Logistics support capability further strengthened. Document management, confidential, confidentiality, duty, letters and other items have been significantly improved. 4, Office construction increased at all levels. City Government offices adhere to strengthen and improve the construction of the system as a breakthrough, has developed a series of code of conduct, continuous improvement of operational mechanism, sound and the implementation of the rules and regulations, and adhere to the system of managing people, according to the rules, the work gradually into the orbit of institutionalization and standardization. Focus on strengthening ideological and political construction of the contingent of cadres, and actively carried out various business training, knowledge of the Office team structure has been optimized, to broaden the range of knowledge and operational capacity grows, nurtured a political firm, sharp, professional and innovative staff, created solidarity, striving for the top, pragmatic, dedication, good image. However, with the State Council and the provincial Government of the national, the province's Secretary-General meeting of government offices under the new situation C1F= C2 300 反馈系数F不宜过大或过小，一般经验数据F?0.1,0.5,本实验取F= ,0.310005.克拉泼和西勒振荡电路 图2-2为串联改进型电容三点式振荡电路——克拉泼振荡电路。 图2-3为并联改进型电容三点式振荡电路——西勒振荡电路。 VCCVCC RCRCRb1b1R3C C1C1L CbReCCbReRb2C2C2CRb2 图2-2 克拉泼振荡电路 图2-3 西勒振荡电路 6(电容三点式LC振荡器实验电路 电容三点式LC振荡器实验电路如图2-4所示。图中3K05打到“S”位置(左侧)时为改进型克拉泼振荡电路，打到“P”位置(右侧)时，为改进型西勒振荡电路。3K01、3K02、3K03、3K04控制回路电容的变化。调整3W01可改变振荡器三极管的电源电压。3Q02为射极跟随器。3TP02为输出测量点，3TP01为振荡器直流电压测量点。3W02用来改变输出幅度。 guide sex further enhanced, documents handle and running of speed obviously speed up, program gradually specification, conference service and Chief reception of quality and level has has new of improve, Logistics support capability further strengthened. Document management, confidential, confidentiality, duty, letters and other items have been significantly improved. 4, Office construction increased at all levels. City Government offices adhere to strengthen and improve the construction of the system as a breakthrough, has developed a series of code of conduct, continuous improvement of operational mechanism, sound and the implementation of the rules and regulations, and adhere to the system of managing people, according to the rules, the work gradually into the orbit of institutionalization and standardization. Focus on strengthening ideological and political construction of the contingent of cadres, and actively carried out various business training, knowledge of the Office team structure has been optimized, to broaden the range of knowledge and operational capacity grows, nurtured a political firm, sharp, professional and innovative staff, created solidarity, striving for the top, pragmatic, dedication, good image. However, with the State Council and the provincial Government of the national, the province's Secretary-General meeting of government offices under the new situation guide sex further enhanced, documents handle and running of speed obviously speed up, program gradually specification, conference service and Chief reception of quality and level has has new of improve, Logistics support capability further strengthened. Document management, confidential, confidentiality, duty, letters and other items have been significantly improved. 4, Office construction increased at all levels. City Government offices adhere to strengthen and improve the construction of the system as a breakthrough, has developed a series of code of conduct, continuous improvement of operational mechanism, sound and the implementation of the rules and regulations, and adhere to the system of managing people, according to the rules, the work gradually into the orbit of institutionalization and standardization. Focus on strengthening ideological and political construction of the contingent of cadres, and actively carried out various business training, knowledge of the Office team structure has been optimized, to broaden the range of knowledge and operational capacity grows, nurtured a political firm, sharp, professional and innovative staff, created solidarity, striving for the top, pragmatic, dedication, good image. However, with the State Council and the provincial Government of the national, the province's Secretary-General meeting of government offices under the new situation 3TP01 13U011Vin3+12V1+5V GND23C14 3R083R09 3W013C133C15 3D01 3R073C043C103R03 3L01S3K05A3R013TP02P3R05S3C1113C023K05B3Q013Q023P01POUT220P3C12输出 1000P3R023K013K023K033K043W023R065103R043C033C01 3C063C073C083C09GND1 1 图2-4 LC振荡器实验电路 the functions and priorities compared to the requirements of our gap is still very big. Main is daily in the passive meet of more, active research of less, service also has not timely, and not in place of problem; work in the meet Yu traditional of, and program of of work way, develop innovation spirit and service innovation capacity not strong; supervision information work and promoted decision implementation of contact enough close, feedback situation not active; research resources of using enough full, research results of into degree not high; some sector documents running not specification; Municipal Government Office on the County (district) and municipal government sector Office work of guide enough, No real form interaction and close collaboration, promote the implementation of the work. These problems, we must effectively be addressed in the future work. Second, serve the overall situation, carry out their duties, improve quality, and strive to create a new situation of system of government offices in the city since last season, meeting the Secretary-General of the State Council and the provincial government has held a government system, from a global and strategic height, scientifically analyzed the new situation and the newTasks on the system of government offices bring new situations and new problems and new challenges, profoundly expounded the work of government departments at all levels in the new era should be put in the situation to understand, to grasp, to deploy at any time and under any circumstances, should always focus on the big picture, firmly grasp the overall situation, increasing in the overall implementing in earnest the work of spontaneity, initiative and steadfastness. And explicitly put forward the "surrounding situation, pay attention to implementation" is the core of government offices, requiring government departments at all levels cannot be "Gramophone", "mail room" and "the Messenger" is not confined to paper communications, yinglaisongwang and upload issue. Must to has strongly of implementation 四、实验内容 1(用示波器观察振荡器输出波形，测量振荡器电压峰—峰值V，并以频率计测量振荡P-P 频率。 2(测量振荡器的幅频特性。 3(测量电源电压变化对振荡器频率的影响。 五、实验步骤 1(实验准备 插装好LC振荡器模块，按下开关3K1接通电源，即可开始实验。 2(西勒振荡电路幅频特性的测量 示波器接3TP02，频率计接振荡器输出口3P01。电位器3W02反时针调到底，使输出最大。开关3K05拨至右侧，此时振荡电路为西勒电路。3K01、3K02、3K03、3K04分别控制3C06(10P)、3C07(50P)、3C08(100P)、3C09(200P)是否接入电路，开关往上拨为接通，往下拨为断开。四个开关接通的不同组合，可以控制电容的变化。例如3K01、3K02往上拨，其接入电路的电容为10P+50P=60P。按照表3-1电容的变化测出与电容相对应的振荡频率和输出电压(峰一峰值V)，并将测量结果记于表2-1(A)中。 P-P 表2-1 电容C(pf) 10 50 100 150 200 250 300 350 振荡频率f(MHZ) 输出电压VP-P(v) 注:如果在开关转换过程中使振荡器停振无输出，可调整3W01，使之恢复振荡。 3(克拉泼振荡电路幅频特性的测量 将开关3K05拨至左侧，振荡电路转换为克拉泼电路。按照上述，测出振荡频率和输出电压，并将测量结果记于表2-1(B)中。 电容C(pf) 10 50 100 150 200 250 300 350 第 5 页 共 6 页 QSGP-A型说明 振荡频率f(MHZ) 输出电压VP-P(v) 4(测量电源电压变化对振荡器频率的影响 分别将开关3K05打至左测(S)和右侧(P)位置，改变电源电压E，测出不同E下的CC振荡频率。并将测量结果记于表3-2中。 其方法是:频率计接振荡器输出3P01，电位器3W02反时计调到底，选定回路电容为50P。即3K02往上拨。用万用表直流电压档测3TP01测量点电压，按照表3-2给出的电压值Ec，调整3W01电位器，分别测出与电压相对应的频率。表中?f为改变Ec时振荡频率的偏移，假定Ec=10.5V时 ,?f=0，则?f=f-f。 10.5V 表2-2 E(V) 10.5 9.5 8.5 7.5 6.5 5.5 C 串联(S) F(MHZ) ?f(KHZ) E(V) 10.5 9.5 8.5 7.5 6.5 5.5 C 并联(P) F(MHZ) ?f(KHZ) 六、实验 1(根据测试数据，分别绘制西勒振荡器，克拉泼振荡器的幅频特性曲线，并进行比较。 3(对实验中出现的问题进行分析判断。 4(由本实验所获提的体会。 6