Kev siv digital oscilloscope yuav tsum tau them sai sai rau qhov teeb meem
1. Taw qhia
Kev siv cov oscilloscopes digital tau dhau los ua neeg nyiam vim lawv qhov tshwj xeeb zoo xws li waveform triggering, cia, tso saib, ntsuas, waveform cov ntaub ntawv tsom xam thiab ua. Vim muaj qhov sib txawv loj ntawm cov oscilloscopes thiab analogue oscilloscopes, yog tias lawv tsis siv kom raug, lawv yuav tsim cov kev ntsuas loj, yog li cuam tshuam rau txoj haujlwm kuaj.
2, paub qhov txawv ntawm analogue bandwidth thiab digital real-time bandwidth
Bandwidth yog ib qho tseem ceeb tshaj plaws ntsuas ntawm oscilloscopes. Lub bandwidth ntawm ib qho analogue oscilloscope yog tus nqi ruaj khov, thaum bandwidth ntawm digital oscilloscope muaj ob hom analogue bandwidth thiab digital real-time bandwidth. Qhov siab tshaj plaws bandwidth uas tuaj yeem ua tiav los ntawm cov oscilloscope digital siv cov txheej txheem sib txuas lossis random sampling cov txheej txheem rau cov cim rov ua dua yog cov digital real-time bandwidth ntawm oscilloscope. Cov digital real-time bandwidth muaj feem xyuam rau qhov siab tshaj plaws digitizing zaus thiab waveform reconstruction txheej txheem K (digital real-time bandwidth=qhov siab tshaj digitizing tus nqi / K), uas feem ntau tsis muab ncaj qha raws li qhov taw qhia.
Los ntawm cov ntsiab lus ntawm ob lub bandwidths, nws tuaj yeem pom tau tias qhov analogue bandwidth tsuas yog tsim nyog rau kev ntsuas ntawm cov teeb liab rov ua dua lub sijhawm, thaum lub sijhawm digital real-time bandwidth tsim nyog rau ob qho tib si rov ua dua cov cim thiab ib qho kev txhaj tshuaj. Cov neeg tsim khoom thov hais tias qhov bandwidth ntawm oscilloscopes tuaj yeem ncav cuag ntau npaum li cas megabytes, qhov tseeb, yog hais txog qhov analogue bandwidth, digital real-time bandwidth qis dua tus nqi no. Piv txwv li, lub bandwidth ntawm TEK's TES520B yog 500MHz, uas yog hais txog nws cov analogue bandwidth ntawm 500MHz, thaum lub siab tshaj plaws digital real-time bandwidth tsuas yog ncav cuag 400MHz, uas nyob deb ntawm cov analogue bandwidth. Yog li ntawd, thaum ntsuas ib lub teeb liab, nco ntsoov xa mus rau cov digital real-time bandwidth ntawm digital oscilloscope, txwv tsis pub nws yuav ua rau qhov tsis zoo rau kev ntsuas.
3, hais txog tus nqi piv txwv
Tus nqi piv txwv, tseem hu ua tus lej digitizing, hais txog chav tsev ntawm lub sijhawm, tus naj npawb ntawm cov qauv ntawm cov lus qhia analogue, feem ntau qhia hauv MS / s. Tus nqi piv txwv yog qhov taw qhia tseem ceeb ntawm cov oscilloscopes.
(1) Yog tias qhov ntsuas qhov ntsuas tsis txaus, qhov tshwm sim sib xyaw yog qhov yooj yim tshwm sim.
Yog hais tias lub teeb liab input ntawm oscilloscope yog 100KHz sinusoidal teeb liab, oscilloscope qhia lub teeb liab zaus ntawm 50KHz, qhov no yuav ua li cas? Qhov no yog vim qhov piv txwv ntawm oscilloscope qeeb dhau, uas ua rau muaj qhov tshwm sim ntawm aliasing. Kev sib xyaw yog qhov zaus ntawm lub waveform tso tawm ntawm lub vijtsam yog qis dua qhov zaus ntawm lub teeb liab, lossis txawm tias oscilloscope ntawm qhov taw qhia taw qhia tau teeb, thiab cov duab ntawm lub waveform tseem tsis ruaj khov. Cov tiam ntawm kev sib xyaw yog qhia hauv daim duab 1.
Yog li, rau lub waveform ntawm tsis paub zaus, yuav ua li cas los txiav txim seb lub waveform tso tawm tau tsim ib qho kev sib xyaw? Nws tuaj yeem ua tau los ntawm maj mam hloov qhov cheb ceev t / div mus rau lub sijhawm nrawm dua, saib seb qhov zaus ntawm lub waveform hloov pauv sai, yog tias muaj, nws txhais tau tias qhov sib xyaw waveform twb tshwm sim lawm; los yog lub wobbling waveform stabilizes ntawm lub sij hawm sai dua, uas kuj txhais tau hais tias lub waveform mixing twb tshwm sim. Raws li Nyquist's theorem, tus nqi piv txwv yuav tsum yog tsawg kawg 2 zaug siab dua qhov siab-zaum feem ntawm lub teeb liab kom tsis txhob sib xyaw, piv txwv li, 500MHz teeb liab xav tau tsawg kawg 1GS / s sampling tus nqi. Muaj ntau txoj hauv kev los tiv thaiv kev sib xyaw kom tsis txhob tshwm sim hauv txoj hauv kev yooj yim:
ib. Kho tus nqi cheb;
b. Siv Autoset;
c. Sim hloov txoj kev sau mus rau lub hnab ntawv lossis Peak Detection, txij li lub hnab ntawv nrhiav qhov muaj txiaj ntsig zoo hauv ntau cov ntaub ntawv sau thiab Peak Detection nrhiav qhov siab tshaj plaws thiab qhov tsawg kawg nkaus hauv ib daim ntawv sau cia, ob qho tib si tuaj yeem tshawb pom cov teeb liab hloov pauv sai.
Yog hais tias lub oscilloscope muaj ib txoj kev sau InstaVu, nws tuaj yeem siv tau vim tias txoj kev no khaws cov waveforms sai sai, thiab cov waveforms tso tawm nrog cov qauv no zoo ib yam li cov uas pom nrog ib qho analogue oscilloscope.
(2) Kev sib raug zoo ntawm tus nqi piv txwv thiab t / div
Qhov siab tshaj qhov piv txwv ntawm txhua lub oscilloscope digital yog tus nqi ruaj khov. Txawm li cas los xij, ntawm ib lub sij hawm luam t/div, tus nqi piv txwv fs yog muab los ntawm cov qauv hauv qab no: fs=N/(t/div) N yog cov ntsiab lus piv txwv ntawm ib lub thav duab.
Thaum tus naj npawb ntawm cov ntsiab lus piv txwv N yog ib qho nqi, fs yog inversely proportional rau t/div, qhov loj dua qhov cheb ceev, qhov qis dua tus qauv.
Hauv cov ntsiab lus, thaum siv cov oscilloscope digital, txhawm rau kom tsis txhob sib xyaw, nws yog qhov zoo tshaj plaws los tso lub cheb ceev iav nyob rau hauv txoj hauj lwm sai. Yog tias koj xav ntes cov burrs fleeting, qhov cheb ceev yog qhov zoo tshaj plaws nyob rau hauv txoj hauj lwm qeeb ntawm lub ntsiab cheb ceev.
