电子专业英语Lesson 8 Clock Sources.ppt

Unit 3 Electronic System ComponentsLesson 8 Clock Sources《电子信息工程专业英语教程》任治刚 主编电子工业出版社 10/21/20231 Lesson 8 Clock SourcesBackgroundsText tour Language in useVocabulary Structure Reading/writing techniques10/21/20232 Terminology Oscillator TCXO, PLL, VCODetector Backgrounds10/21/20233 Terminology 10/21/20234 Oscillator 振荡器Resonant 谐振的Series Resonant 串联谐振Parallel Resonant 并联谐振Resonating frequency 谐振频率Oscillator 10/21/20235 TCXO: Temperature Compensated Crystal Oscillator 温度补偿晶体振荡器PLL: Phase Locked Loop 锁相环VCO: Voltage Controlled Oscillator 压控振荡器TCXO, PLL, VCO10/21/20236 detector n.检测器，检波器，探测元件phase detector n.鉴相器, 相位检测器frequency detector n.鉴频器, 频率检测器Detector 10/21/20237 Outline Clock DevicesCrystals, Crystal Oscillators, Compensated Oscillators, Voltage Controlled Oscillator, Frequency Synthesizers, Clock Buffers Clock ParametersClock Jitter, Skew, Tolerance/Accuracy, Stability, Aging, Slew, Duty CycleText tour 10/21/20238 A basic piezoelectric quartz crystal Two kinds of crystals Series ResonantParallel ResonantClock DevicesCrystals10/21/20239 An oscillator with the crystal as the feedback element Provides the most accurate and stable output frequency. The preferred clock source in most high-speed digital systems requiring clocks.Clock DevicesCrystal Oscillators10/21/202310 Try to adjust the variation in frequency due to temperature and voltage Temperature Compensating Oscillators (TCXO) Clock DevicesCompensated Oscillators10/21/202311 The output of VCO is controlled by a voltage control input pin. Clock DevicesVoltage Controlled Oscillator10/21/202312 Use one or more PLL to generate one to many different frequencies on their outputs, from one or more reference sources. A PLL has two inputsa reference input a feedback input.A PLL corrects frequency in two ways frequency correctionPhase correctionClock DevicesFrequency Synthesizers10/21/202313 Figure 3.4. Block Diagram of a Phase Locked LoopClock DevicesFrequency Synthesizers10