L2 电子系统设计实例研究

1Lecture2:[e-mail]2005SpringEE109ElectronicSystemDesign2Outline„1.Review„2.CaseStudy–DigitalFrequencymeter„CaseStudy1:SystemRequirementAnalysis„CaseStudy2:SystemDesign„CaseStudy3:SubSystemDesign„CaseStudy4:SoftwareDesign„CaseStudy5:SystemTest„CaseStudy6:Document„3.DesignTips„4.Summary2005SpringEE109ElectronicSystemDesign3„1.Review2005SpringEE109ElectronicSystemDesign41.Review：电子系统的组成2005SpringEE109ElectronicSystemDesign51.ReviewExample：一种单片机为核心的电子系统2005SpringEE109ElectronicSystemDesign61.Review:设计方法•功能要求•总体框图•子系统•单元电路•选芯片•原理图•电路仿真•PCB图•单元调试•系统调试•反复TopDownBottomUpDebugIntegrate2005SpringEE109ElectronicSystemDesign71.Review:ProcessofDesign•行为级描述与设计•结构级描述与设计•物理级描述与设计•系统级设计•子系统设计•系统集成测试2005SpringEE109ElectronicSystemDesign8„2.CaseStudy2005SpringEE109ElectronicSystemDesign92.CaseStudy:DigitalFrequencyMeter„CaseStudy1:SystemRequirementAnalysis„CaseStudy2:SystemDesign„CaseStudy3:SubSystemDesign„CaseStudy4:SoftwareDesign„CaseStudy5:SystemTest„CaseStudy6:Document2005SpringEE109ElectronicSystemDesign102.1CaseStudy1:SystemRequirementAnalysis1DigitalFrequencyMeter(Cymometer)„SystemRequirement2005SpringEE109ElectronicSystemDesign112.1CaseStudy1:SystemRequirementAnalysis2RequirementAnalysis„MainFunction„Frequency/Period/PulseWidth/Duty„MainSpecification„DutyError=1%,othersError0.1%„FrequencyRange:1Hz~10MHz„AdvancedFunction:0.1Hz~10MHz„PulseWidth=100us„GateTime:10s„RefreshDisplay:1~10s„InputLevel:0.5~5V„Advanced:0.02V~5V2005SpringEE109ElectronicSystemDesign122.2CaseStudy2:SystemDesign1.MeasurePrincipleStudy„DirectAlgorithm„IndirectAlgorithm„MulticycleSynchronizationAlgorithm2005SpringEE109ElectronicSystemDesign132.2CaseStudy2:SystemDesign2.DirectAlgorithmforFrequency„Diagram„FormulaFx=N/Tx∆Fx/Fx=(1/TsFx+|∆Fc/Fc|)FxGateAMPReshape1|0GateTime1ms/10ms/0.1S/1s/10sFcRSCounterDisplayTxN2005SpringEE109ElectronicSystemDesign142.2CaseStudy2:SystemDesign3.DirectAlgorithmforPeriod„Diagram„Formula„Tx=NT0/K„∆Tx/Tx=(T0Fx/K+|∆Fc/Fc|+0.32/K*Power(10,-SNR/20)FxFcTriggerErrorGateAMPReshape1|0FreqDiv/FreqmultipleCounterDisplay/KT0K*TxNT02005SpringEE109ElectronicSystemDesign152.2CaseStudy2:SystemDesign4.IndirectAlgorithmforFreq/Period„FrequencyÆPeriod„PeriodÆFrequency„Fm„MiddleFrequency„ErrorFigure2005SpringEE109ElectronicSystemDesign162.2CaseStudy2:SystemDesign5.MulticycleSynchronizationAlgorithm„Diagram„Formula„Fx=Na*Fc/Nb„∆Fx/Fx=∆Tx/Tx=Tc/T+|∆Fc/Fc|+0.32/K*Power(10,-SNR/20)GateAAMPReshapeDQClkClkGeneratorFcCounterANa=FxTGateBCounterBNb=FcTPresetPulseFxFxFx=Na*Fc/NbDisplay„Set:Fc=10M,T=1s-Tc/T=0.1us/1s~10E-7„|∆Fc/Fc|~10E-7,TriggerError~0„So:∆Fx/Fx~10E-7,Excellent!2005SpringEE109ElectronicSystemDesign172.2CaseStudy2:SystemDesign6.CoreAlgorithmSelectionDivisionMiddleGoodM.SSwitch@FmDivisionMiddleEnoughIndirectNoLow×DirectSoftwareReq.ComplexErrorAlgorithm2005SpringEE109ElectronicSystemDesign182.2CaseStudy2:SystemDesign6.CoreAlgorithmDoubleCheckDoubleCheck„PulseWidth„Duty„AdvancedRequirement„OtherSpecifications…2005SpringEE109ElectronicSystemDesign192.2CaseStudy2:SystemDesign7.SystemDiagram(1)FrequencyMeter(MulticycleSynchronizationMeasureCore)LEDDisplayKey/SelectionFxbFxa„Hardware?„Division?„Software?„10MHz„Hardware/Software?„10MHz/Division2005SpringEE109ElectronicSystemDesign202.2CaseStudy2:SystemDesign7.SystemDiagram(2)MulticycleSynchronizationMeasureCoreLEDDisplayKey/SelectionFxbFxaMCUChannelAChannelBPowerInputChannelAnalogSubsystemMeasureCoreDigitalSubsystemControllerMCUSubsystemPrincipleStudyAlgorithmSelectionSystemDiagramSubsystemPartition2005SpringEE109ElectronicSystemDesign212.3CaseStudy3:SubSystemDesign(1)„AnalogSubsystem„InputChannel2005SpringEE109ElectronicSystemDesign222.3CaseStudy3:SubSystemDesign(1)1.InputChannelRequirement„Type„AnalogSubsystem„Requirement„Function„ConvertAnalogSignaltoDigitalSignal„Specification„Inputsignal„Level:0.5V~5V,Advanced:0.02V~5VAdvanced:0.02V~5V„Freq:0.1Hz~10MHz,„Outputsignal„Level:TTL„Freq:0.1Hz~10MHzAmplifierReshapeFxTTL2005SpringEE109ElectronicSystemDesign232.3CaseStudy3:SubSystemDesign(1)2.InputChannelDiagramAmplifierReshapeTTLFxInputBufferInputProtection„HighimpedanceSensitivityAdjustTriggerLevelAdjustAdvancedLevel0.02VOutBufferPos+/Neg-PulseEdge2005SpringEE109ElectronicSystemDesign242.3CaseStudy3:SubSystemDesign(1)3.InputChannel:Amplifier+Reshape„Reshape@0.02Vinput„TTL:„TriggerLevel=2V„Gain=2V/0.02V=100„Comparator„MAX902,SR=0.5V/s„SR=2*Pi*Fx*UmÆUm=0.8V@Fx=0.1Hz„Gain=0.8v/(0.02V*1.414)=30„ChooseGain=40@0.02inputReshape=Comparator402005SpringEE109ElectronicSystemDesign252.3CaseStudy3:SubSystemDesign(1)4.InputChannel:AmplifierDoubleCheck„Amplifier„@5VUm=40*5v*1.414=280V„@0.5VUm=40*0.5*1.414=28V„@0.02VUm=40*0.02*1.414=1.2V4/40„„GBW:GAIN*BWGBW:GAIN*BW„4*10M=40M„40*10M=400M„TooLarge!„Max4016+Max4016„GBW=150M„„GBW=GAIN*BWGBW=GAIN*BW„A1:„1*10M=10M„10*10M=100M„A2„4*10M=40MA11/10A24„GainSwitch„@0.5V~5V„Gain=4„Um=2.8V~28V„@0.02V~0.5V„SetGain=40„Um=1.2V~28V2005SpringEE109ElectronicSystemDesign262.3CaseStudy3:SubSystemDesign(1)5.AnalogSubsystemDesignMa