Digital ECG thiab Lub Plawv Saib Xyuas Lub Plawv: 8 Kauj Ruam

2024 Tus sau: John Day | [email protected]. Kawg hloov kho: 2024-01-30 09:29

CEEB TOOM: Qhov no tsis yog khoom siv kho mob. Qhov no yog rau lub hom phiaj kev kawm tsuas yog siv cov cim ntsuas. Yog tias siv lub ntsuas hluav taws xob no rau ntsuas ECG tiag tiag, thov xyuas kom lub Circuit Court thiab Circuit-to-instrument txuas tau siv roj teeb lub zog thiab lwm yam txheej txheem cais kom raug

Ib qho electrocardiogram (ECG) sau cov cim hluav taws xob thaum lub plawv dhia. Txhua lub sijhawm lub plawv dhia, muaj lub voj voog ntawm kev tshem tawm thiab ua kom lub siab sib txawv ntawm cov cell myocardial. Kev tshem tawm thiab ua kom siab dua tuaj yeem raug kaw los ntawm cov hluav taws xob, thiab cov kws kho mob nyeem cov ntaub ntawv ntawd kom kawm paub ntau ntxiv txog lub plawv ua haujlwm li cas. Ib qho ECG tuaj yeem txiav txim siab myocardial infarction, atrial lossis ventricular fibrillation, tachycardia, thiab bradycardia [1]. Tom qab txiav txim siab qhov teeb meem yog los ntawm ECG, cov kws kho mob tuaj yeem ua tiav kuaj mob thiab kho tus neeg mob. Ua raws cov theem hauv qab no kom paub yuav ua li cas thiaj ua rau koj tus kheej lub tshuab ntsuas hluav taws xob ntsuas hluav taws xob!

Kauj ruam 1: Cov ntaub ntawv

Cheebtsam Cheebtsam:

• Tsib UA741 cov haujlwm ua haujlwm siab
• Resistors
• Capacitors
• Jumper xov hlau
• DAQ pawg thawj coj saib
• LabVIEW software

Cov cuab yeej ntsuas:

• Muaj nuj nqi generator
• DC fais fab mov
• Oscilloscope
• BNC cables thiab T-splitter
• Jumper cables
• Cov nab kuab
• Txiv tsawb ntsaws

Kauj Ruam 2: Kev Ntsuas Hluav Taws Xob

Thawj theem ntawm Circuit Court yog lub tshuab ntsuas suab nrov. Qhov no nthuav dav cov teeb meem lom neeg kom qhov sib txawv ntawm ECG tuaj yeem ua qhov txawv.

Daim duab qhia hluav taws xob rau lub ntsuas hluav taws xob ntsuas tau qhia saum toj no. Thawj theem tau txais ntawm qhov Circuit no txhais tias K1 = 1 + 2*R2 / R1. Qhov theem thib ob nce ntawm Circuit Court txhais tias K2 = R4 / R3. Qhov nce tag nrho ntawm qhov ntsuas qhov ntsuas yog K1 * K2. Qhov xav tau nce rau qhov haujlwm no yog kwv yees li 1000, yog li K1 tau xaiv los ua 31 thiab K2 raug xaiv los ua 33. Cov nqi tiv thaiv rau cov txiaj ntsig no tau qhia saum toj no hauv daim duab qhia chaw. Koj tuaj yeem siv qhov ntsuas qhov ntsuas pom saum toj no, lossis koj tuaj yeem hloov kho qhov txiaj ntsig kom tau raws li qhov koj xav tau. **

Thaum koj tau xaiv koj qhov kev tivthaiv qhov tseem ceeb, lub Circuit Court tuaj yeem tsim ua ntawm lub khob cij. Txhawm rau ua kom yooj yim kev sib txuas ntawm lub rooj noj mov, txoj kab tsheb tsis zoo nyob rau sab saum toj tau teeb tsa hauv av thaum ob txoj kab kab rov tav nyob hauv qab tau teeb tsa +/- 15V feem.

Thawj op amp tau muab tso rau sab laug ntawm lub khob cij txhawm rau txhawm rau tawm chaw rau txhua qhov khoom seem. Cov ntawv txuas tau ntxiv nyob rau hauv cov xwm txheej raws sijhawm ntawm tus pin. Qhov no ua rau nws yooj yim dua kom taug qab cov khoom uas tau muab ntxiv lossis tsis yog. Thaum tag nrho cov koob tau ua tiav rau op amp 1, tom ntej op amp tuaj yeem tso tau. Ib zaug ntxiv, xyuas kom tseeb tias nws nyob ze kom thiaj li tawm tau chaw. Tib tus txheej txheem txheej txheem txheej txheem tau ua tiav rau txhua qhov op amps kom txog thaum ntsuas qhov ntsuas qhov ntsuas tau ua tiav.

Bypass capacitors tau ntxiv rau ntxiv rau daim duab qhia chaw kom thiaj li tshem tau AC txuas hauv cov xov hlau. Cov khoom siv hluav taws xob no tau muab tso ua ke nrog DC qhov hluav taws xob thiab muab tso rau ntawm txoj kab tsheb tav toj tsis zoo. Cov capacitors no yuav tsum yog nyob ntawm thaj tsam ntawm 0.1 txog 1 microFarad. Txhua qhov op amp muaj ob qhov hla capacitors, ib qho rau tus pin 4 thiab ib qho rau tus pin 7. Ob lub capacitors ntawm txhua op amp yuav tsum muaj tus nqi zoo ib yam, tab sis tuaj yeem sib txawv ntawm op amp rau op amp.

Txhawm rau ntsuas qhov kev nthuav dav, lub tshuab hluav taws xob muaj nuj nqi thiab oscilloscope tau txuas nrog cov tswv yim thiab tso tawm ntawm lub tshuab hluav taws xob feem. Lub teeb liab nkag tau txuas nrog lub oscilloscope. Ib qho yooj yim sine yoj tau siv los txiav txim siab ua kom nrov nrov. Nkag mus rau lub tshuab hluav taws xob ua haujlwm tso rau hauv ob lub qhov hluav taws xob ntawm qhov ntsuas qhov ntsuas. Teem lub oscilloscope los ntsuas qhov sib piv ntawm cov teeb liab tso tawm rau cov teeb liab tawm tswv yim. Qhov tau txais ntawm Circuit hauv decibels yog Gain = 20 * log10 (Vout / Vin). Rau qhov nce ntawm 1000, qhov nce hauv decibels yog 60dB. Siv lub oscilloscope, koj tuaj yeem txiav txim siab seb qhov kev nce qib ntawm koj lub tsev tsim hluav taws xob ua tau raws li koj qhov tshwj xeeb, lossis yog tias koj xav tau hloov qee qhov kev tiv thaiv tus nqi los txhim kho koj lub Circuit Court.

Thaum cov cuab yeej ntsuas qhov ntsuas tau sib dhos ua haujlwm tau zoo thiab ua haujlwm tau zoo, koj tuaj yeem txav mus rau ntawm lub ntsej muag lim.

** Hauv daim duab kab lus saum toj no, R2 = R21 = R22, R3 = R31 = R32, R4 = R41 = R42

Kauj Ruam 3: Ntsis Lim

Lub hom phiaj ntawm lub taub ntim lim yog tshem tawm suab nrov los ntawm 60 Hz phab ntsa fais fab mov. Lub lim dej thais ua rau lub teeb liab ntawm qhov txiav tawm zaus, thiab hla ntau zaus saum toj thiab hauv qab nws. Rau lub voj voog no, qhov xav tau txiav tawm zaus yog 60 Hz.

Kev tswj hwm qhov sib npaug rau daim duab kos duab qhia saum toj no yog R1 = 1 / (2 * Q * w * C), R2 = 2 * Q / (w * C), thiab R3 = R1 * R2 / (R1 + R2), qhov twg Q yog qhov ua tau zoo thiab w yog 2 * pi * (txiav tawm zaus). Qhov zoo tshaj ntawm 8 muab tus tiv thaiv thiab tus nqi hluav taws xob hauv qhov tsim nyog. Tus nqi hluav taws xob tuaj yeem kwv yees rau txhua yam zoo ib yam. Yog li, koj tuaj yeem xaiv tus nqi hluav taws xob muaj nyob hauv koj cov khoom siv. Qhov ntsuas qhov ntsuas pom hauv Circuit Court saum toj no yog rau kev txiav tawm ntawm 60 Hz, qhov ua tau zoo ntawm 8, thiab tus nqi hluav taws xob ntawm 0.22 uF.

Txij li cov capacitors ntxiv nyob rau hauv parallel, ob lub capacitors ntawm tus nqi xaiv C tau muab tso rau hauv qhov sib npaug kom ua tiav tus nqi ntawm 2C. Tsis tas li, bypass capacitors tau ntxiv rau op amp.

Txhawm rau ntsuas lub lim dej thais, txuas cov khoom siv los ntawm lub tshuab hluav taws xob ua haujlwm rau cov tswv yim ntawm lub hauv paus lim. Saib xyuas cov tswv yim thiab tso tawm ntawm Circuit Court ntawm oscilloscope. Txhawm rau kom muaj lub ntsej muag lim zoo, koj yuav tsum tau txais qhov tsawg dua lossis sib npaug rau -20dB ntawm qhov txiav tawm zaus. Txij li cov khoom tsis zoo tagnrho, qhov no tuaj yeem nyuaj ua tiav. Kev suav tus tiv thaiv thiab tus nqi hluav taws xob yuav tsis muab rau koj qhov kev xav tau. Qhov no yuav xav kom koj hloov pauv tus tiv thaiv thiab tus nqi hluav taws xob.

Txhawm rau ua qhov no, tsom mus rau ib feem ntawm ib lub sijhawm. Ua kom nce thiab txo tus nqi ntawm ib qho khoom siv yam tsis hloov pauv lwm tus. Saib xyuas qhov cuam tshuam qhov no muaj rau qhov nce ntawm Circuit. Qhov no yuav xav tau kev ua siab ntev ntau kom ua tiav qhov xav tau. Nco ntsoov, koj tuaj yeem ntxiv cov neeg tawm tsam hauv koob ntxiv lossis txo tus nqi tiv thaiv. Qhov kev hloov pauv uas txhim kho peb qhov tau txais txiaj ntsig tshaj plaws yog nce ib qho ntawm cov capacitors rau 0.33 uF.

Kauj Ruam 4: Tsawg Pass Lim

Lub lim qis dhau tshem tawm cov suab nrov ntau dua uas tuaj yeem cuam tshuam nrog ECG teeb liab. Kev txiav qis dhau ntawm 40 Hz yog txaus los ntes ECG cov ntaub ntawv xov xwm. Txawm li cas los xij, qee qhov ntawm ECG tshaj 40 Hz. Kev txiav tawm 100 Hz lossis 150 Hz kuj tseem siv tau [2].

Cov lim qis dhau los tsim yog Qhov Kev Txiav Txim Thib Ob Butterworth. Txij li qhov tau txais ntawm peb qhov kev txiav txim siab tau txiav txim siab los ntawm cov cuab yeej ntsuas qhov ntsuas, peb xav tau qhov nce ntawm 1 hauv cov qhab nias rau lim qis. Rau qhov tau txais txiaj ntsig ntawm 1, RA luv luv ncig thiab RB tau qhib ncig hauv daim duab hluav taws xob saum toj no [3]. Hauv Circuit Court, C1 = 10 / (fc) uF, qhov twg fc yog qhov txiav tawm zaus. C1 yuav tsum tsawg dua lossis sib npaug rau C2 * a^2 / (4 * b). Rau qhov kev txiav txim thib ob Butterworth lim, a = sqrt (2) thiab b = 1. Plugging qhov tseem ceeb rau a thiab b, qhov sib npaug rau C2 ua kom yooj yim dua lossis sib npaug rau C1 / 2. Tom qab ntawd R1 = 2 / [w * (a * C2 + sqrt (a^2 * C2^2 - 4 * b * C1 * C2))] thiab R2 = 1 / (b * C1 * C2 * R1 * w^2), qhov twg w = 2 * pi * fc ua. Kev suav rau lub voj voog no tau ua tiav txhawm rau muab txiav tawm ntawm 40Hz. Resistor thiab capacitor qhov tseem ceeb uas ua tau raws cov lus qhia tshwj xeeb no tau qhia hauv daim duab qhia saum toj no.

Lub op amp tau muab tso rau ntawm sab xis ntawm lub khob cij vim tias tsis muaj lwm yam ntxiv yuav ntxiv tom qab nws. Resistors thiab capacitors tau ntxiv rau op amp thiaj li ua tiav qhov Circuit Court. Bypass capacitors kuj tau ntxiv rau op amp. Lub davhlau ya nyob twg tau tso tseg tsis muaj dab tsi vim tias cov tswv yim yuav los ntawm cov cim teeb tsa lim tawm. Txawm li cas los xij, rau kev ntsuas lub hom phiaj, xaim tau muab tso rau ntawm tus lej nkag txhawm rau txhawm rau tuaj yeem cais cov lim qis thiab ntsuas nws tus kheej.

Lub sine yoj los ntawm lub tshuab hluav taws xob ua haujlwm tau siv los ua lub teeb liab thiab pom ntawm ntau zaus. Soj ntsuam ob qho kev nkag thiab tso tawm cov cim ntawm lub oscilloscope thiab txiav txim siab qhov nce ntawm Circuit Court ntawm ntau zaus. Rau qhov lim qis dhau, qhov nce ntawm qhov txiav tawm zaus yuav tsum yog -3db. Rau lub voj voog no, kev txiav tawm yuav tsum tshwm sim ntawm 40 Hz. Zaus qis dua 40Hz yuav tsum muaj me ntsis kom tsis muaj qhov ua kom qis hauv lawv cov duab, tab sis raws li qhov nce ntau dua 40 Hz, qhov nce yuav tsum txuas ntxiv mus.

Kauj Ruam 5: Txhim Kho Cov Txheej Txheem Circuit

Thaum koj tau tsim txhua theem ntawm Circuit Court thiab sim lawv tus kheej, koj tuaj yeem txuas lawv txhua tus. Qhov tso tawm ntawm qhov ntsuas qhov ntsuas yuav tsum txuas nrog lub tswv yim ntawm lub taub lim. Qhov tsim tawm ntawm lub ntsej muag lim yuav tsum txuas nrog lub tswv yim ntawm lim qis.

Txhawm rau ntsuas lub Circuit Court, txuas lub tshuab hluav taws xob ua haujlwm rau cov tswv yim ntawm theem ntsuas qhov ntsuas. Saib xyuas cov tswv yim thiab tso tawm ntawm Circuit Court ntawm oscilloscope. Koj tuaj yeem ntsuas nrog lub phiaj xwm ECG ua ntej los ntawm lub tshuab hluav taws xob ua haujlwm, lossis nrog lub sine yoj thiab soj ntsuam qhov cuam tshuam ntawm koj lub Circuit Court. Hauv cov duab oscilloscope saum toj no, txoj kab nkhaus daj yog lub tswv yim yoj yoj, thiab txoj kab nkhaus ntsuab yog qhov tso tawm.

Thaum koj tau txuas tag nrho koj cov theem kev sib tw thiab qhia tau tias nws ua haujlwm tau zoo, koj tuaj yeem txuas cov zis ntawm koj lub Circuit Court mus rau DAQ pawg thawj coj thiab pib ua haujlwm hauv LabVIEW.

Kauj Ruam 6: LabVIEW Txoj Haujlwm

Txoj cai LabVIEW yog txhawm rau txheeb xyuas tus neeg ntaus hauv ib lub 'meter' los ntawm kev sim ua ECG yoj ntawm ntau zaus. Txhawm rau ua haujlwm hauv LabVIEW koj yuav tsum txheeb xyuas txhua yam ntawm cov khoom ua ntej. Ib qho piv rau digital hloov pauv, tseem hu ua cov ntaub ntawv tau txais (DAQ) pawg thawj coj, yuav tsum tau teeb tsa thiab teeb tsa kom ua haujlwm tsis tu ncua. Lub teeb liab tso tawm los ntawm kab hluav taws xob txuas nrog lub tswv yim ntawm DAQ pawg thawj coj. Cov duab kab ntawv yoj hauv LabVIEW txoj haujlwm tau txuas ncaj qha rau cov txiaj ntsig ntawm DAQ tus pab. Cov zis los ntawm DAQ cov ntaub ntawv kuj tseem mus rau tus cim/min tus cim. Lub teeb liab tom qab ntawd dhau los ntawm tus lej ua lej sib npaug. Qhov ntsuas lej ntawm 0.8 yog siv los xam tus nqi pib. Thaum lub teeb liab tshaj 0.8*Qhov siab tshaj plaws, tau pom qhov siab tshaj plaws. Txhua lub sijhawm tus nqi no tau pom nws tau khaws cia hauv qhov ntsuas kab ntawv. Ob lub ntsiab lus cov ntaub ntawv raug khaws cia hauv qhov ntsuas qhov ntsuas thiab tau nkag mus rau hauv tus lej rho tawm cov lej. Kev hloov pauv hauv lub sijhawm tau pom ntawm ob qhov txiaj ntsig no. Tom qab ntawd, txhawm rau suav lub plawv dhia, 60 tau muab faib los ntawm lub sijhawm sib txawv. Qhov ntsuas tus lej, uas tau qhia nyob ib sab ntawm kab ntawv tso tawm, tso tawm lub plawv dhia hauv feeb ib feeb (bpm) ntawm lub teeb liab nkag. Thaum qhov program tau teeb tsa, nws yuav tsum tau muab tso rau sab hauv txuas ntxiv thaum lub voj. Cov tswv yim sib txawv sib txawv muab qhov txiaj ntsig bpm sib txawv.

Kauj Ruam 7: Sau ECG Cov Ntaub Ntawv

Tam sim no koj tuaj yeem tawm tswv yim simulate ECG teeb liab rau hauv koj lub Circuit Court, thiab sau cov ntaub ntawv hauv koj qhov program LabVIEW! Hloov qhov zaus thiab qhov dav ntawm qhov simulated ECG los saib yuav ua li cas cuam tshuam rau koj cov ntaub ntawv kaw tseg. Thaum koj hloov zaus, koj yuav tsum pom kev hloov pauv hauv lub plawv ntsuas. Koj tau ua tiav tsim ECG thiab ntsuas lub plawv dhia!

Kauj Ruam 8: Kev Txhim Kho Ntxiv

Cov cuab yeej tsim ua haujlwm yuav ua haujlwm tau zoo kom tau txais cov cim ECG simulated. Txawm li cas los xij, yog tias koj xav sau cov cim qhia txog roj ntsha (nco ntsoov ua raws li kev ceeb toom kev nyab xeeb uas tsim nyog), yuav tsum hloov kho ntxiv rau cov kab hluav taws xob txhawm rau txhim kho kev nyeem teeb liab. Lub siab dhau lim yuav tsum tau ntxiv kom tshem tawm DC offset thiab cov khoom siv qis qis qis. Qhov nce ntawm qhov ntsuas qhov ntsuas yuav tsum raug txo los ntawm kaum npaug kom nyob hauv thaj tsam siv tau rau LabVIEW thiab op amps.

Qhov chaw

[1] S. Meek thiab F. Morris, “Taw qhia. II-cov ntsiab lus yooj yim., "BMJ, vol. 324, nra. 7335, phab 470–3, Lub Ob Hlis 2002.

[2] Chia-Hung Lin, Zaus-qhov tshwj xeeb rau ECG tuav kev ntxub ntxaug siv kev sib txheeb txheeb cais raws li kev txheeb cais, Hauv Khoos phis tawj & Lej nrog rau Kev Siv, Ntim 55, Qhov Teeb Meem 4, 2008, Nplooj 680-690, ISSN 0898-1221, [3] “Qhov Kev Txiav Txim Thib Ob | Kev Txiav Txim Thib Ob Tsawg Dhau Lim Tsim. " Cov Khoom Siv Hluav Taws Xob yooj yim, 9 Cuaj Hlis 2016, www.electronics-tutorials.ws/filter/second-order-…