Digital Oscilloscopes vs Analogue Oscilloscopes
Cov yam ntxwv zaus ntawm analogue oscilloscopes yog txiav txim los ntawm ntsug amplifiers thiab cathode oscillators. Kev taw qhia txog kev ua digital thiab microprocessors rau oscilloscopes hauv xyoo 1980s coj mus rau qhov tshwm sim ntawm digital oscilloscopes. Analogue oscilloscopes tam sim no hu ua analogue real-time oscilloscopes (ART) thiab cov oscilloscopes yog hu ua digital storage oscilloscopes (DSO).
ART yuav tsum tau sib haum nrog lub bandwidth ntawm lub amplifier thiab cathode ray oscilloscope, nrog rau kev nce nyob rau hauv zaus, cathode ray oscilloscope txheej txheem yuav tsum nruj, tus nqi nce, thiab lub hav zoov ntawm bottlenecks. DSO ntev npaum li qhov bandwidth sib xws nrog lub siab ceev A / D converter, lwm yam kev hloov kho, kev soj ntsuam ntawm cov duab peb sab; waveform nco tsis txaus los cuam tshuam nrog waveform, thiab lwm yam.
Tam sim no, qhov tsis txaus ntawm DSO tau dhau los ua qhov tseem ceeb, tab sis tsis yog txhua qhov kev ua tau zoo tau cuam tshuam los ntawm tib lub oscilloscope, uas yog, txhua DSO yuav muaj qee yam tsis zoo, muaj qee qhov tsis zoo hauv kev xaiv cov qauv yuav tsum tau ua tib zoo saib xyuas. kev sib piv. Qee cov qauv DSO muaj tib qhov hloov pauv hloov pauv hloov pauv raws li ART, thaum qee tus qauv DSO tsis ua, thiab ib qho DSO muaj peev xwm los tso saib peb-dimensional duab ntawm fluorescent screen ntawm ART, thaum feem ntau DSOs tsis muaj qhov kev ua tau zoo. Feem ntau DSOs muaj tib lub sijhawm bandwidth raws li ib lub sijhawm bandwidth, tab sis kuj tseem muaj DSOs uas tsuas lav lub sijhawm bandwidth.
Tag nrho cov DSOs uas tau hais los saum no muaj A/D converters thiab microprocessors. Nyob rau hauv txoj kev no, qhov sib ntxiv ntawm daim npav ntsaws rau hauv lub tshuab pC kuj tseem tuaj yeem tsim DSO, tab sis feem ntau qis dua tus nqi, kev ua haujlwm tsawg dua, thiab pheej yig dua. Tseem muaj DSO modules siv lub npav VXI, nrog rau khib-mounted DSO plug-ins.
DSO nco yog qhov thib ob nkaus xwb rau cov khoom siv oscilloscope hauv A / D converter Cheebtsam, uas txuag cov qauv ntsuas ntsuas rau tom ntej D / A converter los kho cov waveform, thiab tam sim no lub peev xwm cia tuaj yeem ncav cuag ntau dua 1M.
Ordinary DSOs muaj 8-ntsis ntsug kev daws teeb meem, piv txwv li 256 cov qauv ib qho scan, xav tau 256 cov ntsiab lus cia, sib npaug rau 256 bytes. Yog tias koj txhim kho qhov kev daws teeb meem, kab rov tav axis yuav nthuav dav los ntawm 10 npaug, nws yog sib npaug rau 20K bytes; ntsug axis kuj nthuav dav los ntawm 10 npaug, nws yog sib npaug rau 40K bytes. Nws tuaj yeem pom tias DSO yuav tsum yog tsawg kawg yog 2K bytes, thiab qhov nruab nrab DSO yuav tsum ntau dua 40K bytes. Yog tias koj xav sau 10 npaug ntawm cov ntawv saum toj no, ces tsawg kawg yog 400K bytes lossis ntau dua. Yog li ntawd, qhov loj ntawm lub peev xwm cia yog qhov tseem ceeb heev.
Nyob rau hauv lem, lub peev xwm cia kuj cuam tshuam rau scanning ceev, piv txwv li, tsuas yog 50K cov ntsiab lus ntawm lub cim xeeb ib cheb ntawm cov kab, sau 100μs ntawm cov ntaub ntawv, ces qhov sampling spacing yog 2ns, tus nqi piv txwv yog sib npaug rau 500MS / s, mus rau lub sampling tus nqi yog sib npaug rau 4 npaug ntawm bandwidth xam, real-time bandwidth yog sib npaug rau 125MHz. pom tseeb, yog tias koj xav tau los txhim kho tus nqi piv txwv mus rau 1000MS / s, ces cov ntaub ntawv kaw 100μs, yuav tsum yog 100K cov ntsiab lus ntawm kev nco.
Txhawm rau khaws cov duab tiav, cia lub pixel yog 1024 × 512=0.5M cov khoom, plaub daim duab, kom muaj 2M khoom cia. Hauv FFT tsom xam kuj xav tau kev khaws cia ntxiv, cov khoom siv waveform tshiab thiab cov ntaub ntawv siv waveform lossis khaws cia waveform rau kev sib piv. Txhawm rau pab txhawb nqa waveform cia, qee qhov DSOs muab floppy disks lossis hard disks rau cov ntaub ntawv kaw.
