Cov lim dej tsis siv neegtuaj yeem ua los ntawm kev txuas ua ke lub lim dej qis dhau nrog lub lim dej siab dhau
Lub lim dej Passive Band Pass siv tau los cais lossis lim tawm qee qhov zaus uas nyob hauv ib qho band lossis ntau yam zaus. Qhov zaus txiav tawm lossis ƒc taw tes hauv lub lim dej passive RC yooj yim tuaj yeem tswj tau kom raug siv tsuas yog ib qho resistor hauv series nrog lub capacitor tsis-polarized, thiab nyob ntawm seb lawv txuas nrog txoj kev twg, peb tau pom tias tau txais Low Pass lossis High Pass lim.
Ib qho yooj yim siv rau cov hom lim dej passive no yog nyob rau hauv cov ntawv thov suab amplifier lossis circuits xws li hauv cov lim dej crossover loudspeaker lossis pre-amplifier tone controls. Qee lub sij hawm nws yog qhov tsim nyog tsuas yog dhau qee qhov ntau ntawm cov zaus uas tsis pib ntawm 0Hz, (DC) lossis xaus rau qee qhov zaus siab dua tab sis nyob hauv qee qhov ntau lossis band ntawm cov zaus, txawm tias nqaim lossis dav.
Los ntawm kev txuas lossis "cascading" ua ke ib qho Low Pass Filter circuit nrog High Pass Filter circuit, peb tuaj yeem tsim lwm hom passive RC lim uas dhau qhov ntau yam xaiv lossis "band" ntawm cov zaus uas tuaj yeem nqaim lossis dav thaum txo cov neeg sab nraud ntawm qhov ntau yam no. Hom tshiab ntawm kev npaj lim passive no tsim cov lim xaiv zaus hu ua Band Pass Filter lossis BPF luv luv.
Tsis zoo li cov lim dej qis uas tsuas yog hla cov teeb liab ntawm qhov ntau zaus qis lossis cov lim dej siab uas hla cov teeb liab ntawm qhov ntau zaus siab dua, Cov Lim Dej Band Pass hla cov teeb liab hauv qee qhov "band" lossis "kis" ntawm cov zaus yam tsis muaj kev cuam tshuam cov teeb liab nkag lossis qhia txog suab nrov ntxiv. Cov kab no ntawm cov zaus tuaj yeem yog qhov dav thiab feem ntau hu ua cov lim dej Bandwidth.
Bandwidth feem ntau txhais tias yog qhov ntau zaus uas muaj nyob nruab nrab ntawm ob qhov chaw txiav zaus (ƒc), uas yog 3dB qis dua qhov chaw siab tshaj plaws lossis lub ncov resonant thaum ua kom tsis muaj zog lossis qaug zog lwm tus sab nraud ntawm ob lub ntsiab lus no.
Tom qab ntawd rau cov zaus kis tau dav dav, peb tuaj yeem txhais lo lus "bandwidth", BW yog qhov sib txawv ntawm qhov zaus txiav qis dua (ƒcLOWER) thiab qhov zaus txiav siab dua (ƒcHIGHER) cov ntsiab lus. Hauv lwm lo lus, BW = ƒH - ƒL. Nws yog qhov tseeb rau lub lim dej hla kom ua haujlwm tau zoo, qhov zaus txiav ntawm lub lim dej hla qis yuav tsum siab dua qhov zaus txiav rau lub lim dej hla siab.
Lub lim dej Band Pass "zoo tagnrho" kuj tseem siv tau los cais lossis lim tawm qee qhov zaus uas nyob hauv ib pawg zaus tshwj xeeb, piv txwv li, kev tshem tawm suab nrov. Cov lim dej Band pass feem ntau hu ua cov lim dej thib ob, (ob-ncej) vim tias lawv muaj "ob" cov khoom siv reactive, cov capacitors, hauv lawv txoj kev tsim hluav taws xob. Ib lub capacitor hauv lub voj voog qis dhau thiab lwm lub capacitor hauv lub voj voog siab dhau.
Daim duab Bode Plot lossis cov kab teb zaus saum toj no qhia txog cov yam ntxwv ntawm cov lim dej band pass. Ntawm no lub teeb liab raug txo qis ntawm cov zaus qis nrog cov zis nce ntxiv ntawm qhov nqes hav ntawm + 20dB / Decade (6dB / Octave) kom txog thaum lub zaus mus txog qhov "txiav tawm qis dua" ƒL. Ntawm qhov zaus no lub zog tso zis yog dua 1 / √2 = 70.7% ntawm tus nqi teeb liab nkag lossis -3dB (20 * log (VOUT / VIN)) ntawm qhov nkag.
Cov zis txuas ntxiv mus ntawm qhov nce siab tshaj plaws kom txog thaum nws mus txog qhov "sab saud txiav-tawm" ƒH qhov twg cov zis txo qis ntawm tus nqi ntawm -20dB / Decade (6dB / Octave) attenuating txhua lub teeb liab zaus siab. Lub ntsiab lus ntawm qhov tso zis siab tshaj plaws feem ntau yog qhov nruab nrab geometric ntawm ob tus nqi -3dB ntawm qhov qis dua thiab sab saud txiav-tawm thiab hu ua tus nqi "Center Frequency" lossis "Resonant Peak" ƒr. Tus nqi nruab nrab geometric no yog suav tias yog ƒr 2 = ƒ(UPPER) x ƒ(LOWER).
Alim dej hlaraug suav hais tias yog hom lim dej thib ob (ob-ncej) vim nws muaj "ob" cov khoom sib xyaw hauv nws cov qauv hluav taws xob, ces lub kaum sab xis yuav yog ob npaug ntawm cov lim dej thawj zaug uas tau pom yav dhau los, piv txwv li, 180o. Lub kaum sab xis ntawm cov teeb liab tso zis LEADS ntawm cov tswv yim los ntawm +90o mus txog rau qhov chaw nruab nrab lossis zaus resonant, ƒr point yog nws dhau los ua "xoom" degrees (0o) lossis "hauv-theem" thiab tom qab ntawd hloov mus rau LAG cov tswv yim los ntawm -90o thaum cov zaus tso zis nce ntxiv.
Piv txwv li, cov ntsiab lus zaus txiav sab saud thiab qis rau cov lim dej band pass tuaj yeem pom siv cov mis tib yam li rau ob qho tib si cov lim dej qis thiab siab dhau, piv txwv li.
Cov chav tsev tuaj nrog tus qauv SMA lossis N poj niam connectors, lossis 2.92mm, 2.40mm, thiab 1.85mm connectors rau cov khoom siv zaus siab.
Peb kuj tseem tuaj yeem hloov kho lub lim dej Band Pass raws li koj xav tau. Koj tuaj yeem nkag mus rau nplooj ntawv hloov kho kom muab cov lus qhia koj xav tau.
Lub sijhawm tshaj tawm: Cuaj hlis-06-2022
