Vim li cas qhov ntsuas amplitude tsawg dua tus nqi tiag?
Sim ib qho kev sim me me. Siv koj li100 MHz oscilloscopentsuas 100MHz, 3.3V amplitude waveform. Qhov ntsuas amplitude tsis raug. Qhov teeb meem no hais txog lub bandwidth ntawmoscilloscope.
Dab tsi yog bandwidth?
Bandwidth yog ib qho tseem ceeb parameter rau lub oscilloscope, tab sis dab tsi yog bandwidth? Bandwidth yog hais txog qhov analogue bandwidth ntawm analogue pem hauv ntej kawg ntawm oscilloscope, thiab ncaj qha txiav txim siab oscilloscope lub teeb liab ntsuas peev xwm. Tshwj xeeb, oscilloscope bandwidth yog qhov siab tshaj plaws thaum lub amplitude ntawm sine yoj ntsuas los ntawm oscilloscope tsis qis dua 3dB amplitude ntawm qhov tseeb sine yoj teeb liab (piv txwv li 70.7 feem pua ntawm qhov tseeb amplitude), tseem hu ua {{3. }}dB txiav tawm zaus point. Raws li lub teeb liab zaus nce, oscilloscope lub peev xwm los qhia qhov tseeb theem teeb liab yuav txo.
Thaum qhov ntsuas sine yoj zaus sib npaug rau qhov bandwidth ntawm oscilloscope (oscilloscope amplifier yog rau Gaussian teb), peb tuaj yeem pom tias qhov ntsuas qhov yuam kev yog li 30 feem pua. Yog tias qhov ntsuas qhov yuam kev yuav tsum yog 3 feem pua, qhov zaus ntawm qhov ntsuas ntsuas yuav tsum qis dua li oscilloscope bandwidth. Piv txwv li, siv 100MHz oscilloscope los ntsuas 100MHz, 1Vpp, sine yoj teeb liab, qhov ntsuas yuav yog 100MHz, 0.707Vpp, sine waveform. Qhov no tsuas yog rooj plaub rau sine yoj vim tias feem ntau cov qauv waveforms ntau dua li sine yoj lawv yuav muaj ntau dua. Yog li thiaj li ua tiav qhov kev ntsuas qhov tseeb, peb siv cov kev cai oscilloscopes uas feem ntau hu ua 5 npaug ntawm tus qauv:
Qhov xav tau bandwidth ntawm oscilloscope=lub siab tshaj plaws zaus ntawm qhov ntsuas ntsuas * 5
2. Xaiv lub bandwidth kom raug
Cov teeb liab nyuaj nyob rau hauv lub waveform yog tsim los ntawm ntau yam sib txawv harmonic sine wave signals, thiab bandwidth ntawm cov harmonics tej zaum yuav dav heev. Thaum lub bandwidth tsis siab txaus, lub harmonic Cheebtsam yuav tsis zoo amplified (thaiv los yog attenuated), uas tej zaum yuav ua rau amplitude distortion, ntug poob, poob ntawm cov ntaub ntawv nthuav dav, thiab lwm yam. Cov yam ntxwv teeb liab xws li tswb thiab tones, thiab lwm yam. tsis muaj nqi siv.
Yog li, rau qhov sib txawv zaus ntsuas ntsuas, qhov tseeb bandwidth tseem ceeb heev. Thaum ntsuas cov teeb liab ntau zaus, xws li ntsuas 27MHz siv lead ua, koj yuav tsum siv tag nrho qhov ntsuas bandwidth.
Yog tias qhov kev txwv bandwidth tau qhib, uas yog, qhov txwv bandwidth tau teem rau 20MHz, cov siv lead ua waveform yuav raug cuam tshuam thiab qhov ntsuas yuav tsis muaj nqis. Thaum ntsuas cov teeb liab tsawg zaus, koj yuav tsum teeb tsa lub bandwidth txwv kom pab kom lub teeb liab cuam tshuam ntau zaus, qhov no yog qhov teeb liab qhia meej dua.
3. Bandwidth thiab lub sijhawm nce
Hais txog bandwidth, lub sijhawm nce tsis tuaj yeem tsis quav ntsej. Lub sijhawm nce feem ntau txhais tau tias yog lub sijhawm uas lub teeb liab amplitude hloov ntawm 10 feem pua ntawm qhov siab tshaj plaws tus nqi mus rau 90 feem pua.
Lub bandwidth ntawm oscilloscope tuaj yeem ncaj qha qhia qhov tsawg kawg ntawm lub sijhawm nce ntawm lub teeb liab. Lub sijhawm nce ntawm oscilloscope system tuaj yeem ntsuas los ntawm qhov teev bandwidth. Koj tuaj yeem siv cov qauv: RT (lub sijhawm nce)=0.35 / BW (bandwidth) (oscilloscope hauv qab 1GHz) los xam.
Qhov twg 0.35 yog qhov ntsuas qhov ntsuas nruab nrab ntawm oscilloscope bandwidth thiab lub sijhawm nce (10 feem pua -90 feem pua nce sij hawm hauv thawj qhov kev txiav txim Gaussian qauv). Raws li cov qauv saum toj no, yog tias qhov bandwidth ntawm oscilloscope yog 200MHz, tuaj yeem xam RT=1.75ns, uas yog, qhov tsawg kawg nkaus pom lub sijhawm nce.
