模拟电子技术基础8

2004-12-918.1sin-waveoscillator8.2comparator8.38.42004-12-928.1.1.oiXAX′=oAFX=1AF=———12AFAFnπ=∠⎧⎪⎨⎪⎩=*AF18.12004-12-932.→f0//2AFnπ∠=1AFf08.1/f01AF=2004-12-943.Q8.14.RCLC2004-12-95.RCRCRC(RCRCT1.RC12fRCπ→12fRCπ→12fRCπ≈→U2U2U28.12004-12-96012fRCπ=21111////UURRjCRCjjCωωω=++113()jRCRCωω=+−201013()UFffUjff==+−ff013MaxF=0ϕ=8.12004-12-972.Wien-BridgeOscillator012fRCfπ==13MaxF=0ϕ=Au1+Rf/R13UoRf↓R1↑Au31.(Rf(R12.11fdRrAuR+=+8-58-78-88.12004-12-98KRCC_+∆+∞RfuoRCCRKKR1R1R2R2R3R3012fRCπ=8.12004-12-99_+∆+∞RF1uoR1CCRfD1D1RF2R28R27R26R25R24R23R22R21R2123451768.12004-12-910.LC1.LCLCLC8.1L11()RjLjCZjCRjLωωωω=+++11()RLjLLjCjCRωωωωω+−⎯⎯⎯→2004-12-9111()LCRjZLCωω+−=∴0010LCωω−=()012;fLCπ=0LZRC=001LQRRCωω==R8.12004-12-9122.LC012fLCπ=′L′|AF|1LCC18.12004-12-913012fLCπ=′122LLLM′=++ColpittsOscillator8.1012fLCπ=′1212CCCCC′=+HartleyOscillator2004-12-9148.12004-12-9153.SiO2L10-3~10-2HRC0()~pFC10-4~10-1pF1QLRC=10512sfLCπ=12pSooffCCLCCπ=≈+8.12004-12-916CLpFf0→fSCLf0fSfP8.18-128-142004-12-9178.2uIUT8.21.0IuVOOMuU=−0IuVOOMuU=0TUV=2004-12-91807.IdMAXVu=8.2ZOuU=±ZOuU=±2004-12-9192.0()TUV≠;0Ni=∵2112REFINRURuuRR++∴=8.2ITuU=0PNuuV==210REFTRURU+∴=21TREFRUUR→=−2004-12-920ShmittuIUT;0Pi=∵212112RPEFZRURRRUuRR+∴=±+ITuU=PNuu=111222RETZFRUURURRRR∴=±++8.2TU+→=+TU−=−22004-12-921ITuU−ZOuU=ITuU+ZOuU=ITuU+ZOuU=−ITuU−ZOuU=−ITuU−ZOuU=0REFU=112TZRUURR+=+112TZRUURR−=−+8.22004-12-9228-168-178.22004-12-923UTLUTHBJTβ21OOOuuuIRLuUHZOOLUUU~IRLRHuUU=IRHuU0OOLLUULZOOHUUU1.2.8.22004-12-9248.2LM339(139/239)AD790AD9696LM311236V±1±18V5V±5V5V±5V530V±2.5±15V300ns45ns4.5ns200nsOCTTLOC*2004-12-925LM3398.22004-12-9268.38.3uCUT+UT-tUZuOUZ-UZt1T12ZRURUR++=1T12ZRURUR−−+=RCuC0uOUZ1.R3C2.UT+R3C3.UT-R3C8.32004-12-9272004-12-928uCUT+UT-tUZuOUZ-UZt1.ZOuU=±2UZ2.12TTT=+T1T231()(0)ln()()UURCUUtT∞−=∞−3lnZTZTUURCUU+−−−=−−12322lnRRRCR+=122322lnRRTRCR+=123222lnRRTRCR+=∴1fT=212TqT==8.32004-12-9298.32004-12-9308.32RCRC2004-12-931A1A21111222IPORuRRuRuRR++=+∵112TORuUR∴−=ZU±13(0)OOOutuRCu+=−uIUTuP08.32004-12-93212TZURUR±=13(0)OOOutuRCu+=−uC0uO1UZ1.A22.UT-3.UT+2UT+2UZR1/R2T1T21212TTTT+==31ZTTUCTUUR+−−=∵1324RRCRT∴=R3C8.32004-12-933212TqT==uO1D18.38-198-222004-12-934VCOV/F411312()SZDRfTRRUuCU≈=+8.334TDRURU+=34TZRUUR−=−2004-12-935ICL80380.001Hz~1MHz0.1%8.32004-12-9368.4→-11+8.4→2004-12-937→8.42004-12-9388.42004-12-939A1D1D2A2uID1D2uID1D28-25(b)8.4