带通滤波器BandpassFilter

1、Basic Filter Circuits11. High-Pass Filter (高通濾波電路)R XcVin 二VinVinVoutVoltage Gain（電壓放大倍數）=R(1) 3dB FrequencydB =20 log 炖Vin-3 = 20logoutin123dBRCf3dB12 二 RC1 Roll-off Attenuation (衰減斜率)1At low freque ncies,3dB,RCVoutVin：空 RC =3dB= 20logVout(dB) =20logcoor 20 log - log 嗨in3dB3dB)71 、At =2 3dB (called

2、Octave” (八度音),=20 logC3dB= 20log|=_6(dB)= Roll-off Attenuation (衰減斜率)=6 dB/octaveAt “10皿(caHeddecade”),= 20log =20(dB)=Roll-off Attenuation (衰減斜率)=20 dB/decade Phase Shift (相移)VoutRVinR _jeoCThe output voltage,vout, leads ahead of the in put voltagevin, by the an gle Q.,1/C 灼 3dBwhere tan一.R At 用工 1

3、 - 3dB, tan -10 =- : 8410At =10 3dB, tan： = 0.1 =-62. Low-Pass Filter (低通濾波電路)Xcf+Xcj cVinRVin 广* Vout15k QC0.01 mF二 Voltage Gain =outin.2R2C2 1RC(1) 3dB FrequencydB 二 20 log-3 = 20log1212RC3dBRCorf3dB Roll-off Attenuation (衰減斜率)9At high frequencies,门 1RC=3dB ,1RC3dB= 20logVout(dB) =20login3dB iiIo丿

4、or 20log - log20log3dB)At =2 3dB (Octave(八度音),二 20 log3dB20log|-6(dB)=Roll-off Attenuation(衰減斜率)-6 dB/octaveAt * -10 3dB ,= 20log =20(dB)=Roll-off Attenuation (衰減斜率)二-20dB/decade Phase Shift （相移）171當=10 3dB，tan_.1 =63dBThe output voltage,vout, lags beh ind the in put voltage,Vin, by the an gle 0,whe

5、re tan）/ 灼C3dB當=10 ；3dB , tan71 = -10 =- ： -843. Band-Pass Filter 帶通濾波器）LCZlj C100QVout0.01 pF10mHT（尸VoutLCVinZlcjR coCT（）R2 0C -:+1LResonant Freque ncy 共振頻率）:fo,or C0LZlcVout=1Vin13o=JlcQuality factor （品質因數）二0-f3dB（sharp ness of the bell-shape curve）At 3dB point,=1RCThere are two 3dBpo in ts: and 皿2-0RC2-0RC(01)(0 :;J 2)RCfr 二 5