ECG Sau Circuit: 5 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 qhov kev ntsuas no rau kev ntsuas ECG tiag tiag, thov xyuas kom lub Circuit Court thiab Circuit-to-instrument txuas tau siv cov txheej txheem cais tawm kom raug

Tej zaum qhov kev ntsuas lub cev dav tshaj plaws nyob rau niaj hnub no kev lag luam kho mob yog Electrocardiogram (ECG/EKG). Nws nyuaj rau taug kev los ntawm tsev kho mob lossis chav kho mob xwm txheej ceev yam tsis hnov lub suab nrov "beep" ntawm lub plawv dhia saib lossis pom ECG cov duab nthwv dej hla lub vijtsam hauv tus neeg mob chav. Tab sis, qhov ntsuas no yog dab tsi uas tau cuam tshuam nrog kev noj qab haus huv niaj hnub no?

Lub tshuab electrocardiogram feem ntau yuam kev rau kev sau lub cev ua haujlwm ntawm lub plawv, txawm li cas los xij, raws li lub npe qhia tias nws yog qhov sau cia ntawm kev ua haujlwm hluav taws xob, kev tshem tawm thiab rov ua dua tshiab, ntawm lub plawv cov leeg. Los ntawm kev txheeb xyuas cov ntaub ntawv sau tseg, cov kws kho mob tuaj yeem nkag siab txog tus cwj pwm ntawm lub plawv hluav taws xob. Qee qhov kev kuaj mob ua los ntawm ECG cov ntaub ntawv suav nrog: myocardial infarction, pulmonary embolism, arrhythmias, thiab AV blocks.

Cov Lus Qhia hauv qab no yuav piav qhia cov txheej txheem thiab cov hauv paus ntsiab lus siv los tsim cov hluav taws xob hluav taws xob yooj yim uas muaj peev xwm sau ECG nrog kev siv cov nplaim hluav taws xob yooj yim zoo li tau ua hauv tsev kho mob.

Kauj Ruam 1: Tsim Cov Khoom Siv Hluav Taws Xob

Thawj lub hauv paus tseem ceeb yuav tsum tau sau ECG lub teeb liab yog lub ntsuas qhov ntsuas. Cov amplifier no muaj ob qhov cuam tshuam.

1. Nws tsim cov khoom siv hluav taws xob tsis sib xws ntawm cov kab hluav taws xob kaw thiab cov seem hauv Circuit Court. Qhov no txo qhov xav tau tam sim no kos los ntawm cov electrodes mus rau qhov ua haujlwm xoom. Tso cai teeb liab sau nrog qhov cuam tshuam me me los ntawm cov tswv yim cuam tshuam.

2. Nws txawv qhov sib txawv ua kom lub suab kaw tseg. Qhov ntawd txhais tau tias txhua lub teeb liab tshwm sim hauv ob qho kev teev cia hluav taws xob yuav tsis ua kom nrov nrov, thaum qhov sib txawv (qhov tseem ceeb) yuav yog.

Feem ntau qhov ntsuas cov nplaim hluav taws xob rau ECG yuav nyob hauv ntau qhov milliVolt. Yog li, kom tau txais lub teeb liab no mus rau hauv ib puag ncig peb tuaj yeem ua haujlwm nrog kev nthuav dav (K) ntawm 1000 V/V yuav tsim nyog.

Kev tswj hwm qhov sib npaug rau lub tshuab hluav taws xob tau piav qhia saum toj no yog:

K1 = 1 + 2*R2 / R1, qhov no yog theem 1 nce

K2 = - R4/R3, qhov no yog theem 2 nce

Nco ntsoov tias qhov zoo tshaj, K1 thiab K2 yuav tsum yog kwv yees li sib npaug thiab kom ua tiav qhov kev xav tau K1 * K2 = 1000

Qhov txiaj ntsig zaum kawg uas siv hauv peb qhov kev sib tw yog….

R1 = 6.5 kOhm

R2 = 100 kOhm

R3 = 3.17 kOhm

R4 = 100 kOhm

Kauj Ruam 2: Tsim Lub Tshuab Ntsis

Nws zoo li nyob hauv lub ntiaj teb niaj hnub no uas kev sau ECG yuav ua tiav nyob ze qee lwm yam khoom siv hluav taws xob, lossis txawm tias tsuas yog nyob hauv lub tsev uas tau siv hluav taws xob los ntawm cov kab hluav taws xob hauv cheeb tsam. Hmoov tsis zoo, qhov hluav taws xob siab thiab qhov sib txawv ntawm lub zog muab txhais tau tias nws yuav tsim hluav taws xob ntau "suab nrov" hauv kev siv cov khoom siv hluav taws xob uas nyob ze nws; qhov no suav nrog cov xov hlau thiab cov khoom siv hluav taws xob siv los tsim peb cov kab ke ECG sau.

Txhawm rau tawm tsam qhov no, txhua lub teeb liab nrog zaus sib npaug ntawm lub suab nrov uas tau tsim los ntawm lub zog hauv cheeb tsam (hu ua mains hum) tuaj yeem yooj yim lim tawm thiab tshem tawm qhov tseem ceeb. Hauv Tebchaws Meskas, daim phiaj siv hluav taws xob muab 110-120V nrog zaus 60 Hz. Yog li ntawd, peb yuav tsum lim tawm ib qho teeb meem tivthaiv nrog zaus ntawm 60 Hz. Luckily, qhov no tau ua tiav ntau zaus ua ntej thiab tsuas yog xav tau kev tsim ntawm lub thais lim (daim duab saum toj no).

Qhov sib npaug tswj cov lim no yog….

R1 = 1 / (2 * Q * w * C)

R2 = (2 * Q) / (w * C)

R3 = (R1 * R2) / (R1 + R2)

Q = w / B.

qhov twg wc2 yog qhov txiav tawm ntau zaus, w2 qhov txiav tawm tsawg zaus, w qhov txiav tawm zaus hauv rad/sec, thiab Q qhov ua tau zoo

Nco ntsoov tias C yog tus nqi uas tuaj yeem xaiv dawb. Cov txiaj ntsig hauv qab no siv hauv peb qhov kev sib tw yog:

R1 = 1.65 kOhm

R2 = 424.5 kOhm

Q = 8 hli

w = 120 * pi rad/sec

Kauj Ruam 3: Lim-Pass Lim

ECG cov cim qhia muaj zaus ib puag ncig 0 - 150Hz. Txhawm rau tiv thaiv ntau lub suab nrov los ntawm kev txuas mus rau lub teeb liab los ntawm yam uas muaj ntau zaus ntau dua li qhov no, qhov kev xaj thib ob qis dua ButterWorth lim nrog kev txiav tawm ntawm 150Hz tau ua tiav txhawm rau tsuas yog tso cai ECG teeb liab kom dhau los ntawm Circuit Court. Hloov chaw tam sim xaiv qhov muaj peev xwm muaj peev xwm ua tau zoo, zoo li cov khoom siv dhau los, thawj tus nqi hluav taws xob, C2, tau xaiv raws cov qauv pom hauv qab no. Los ntawm tus nqi ntawd, tag nrho lwm qhov txiaj ntsig tuaj yeem suav tau thiab tom qab ntawd ntxiv rau hauv Circuit Court thaum khaws qhov nce ntxiv rau 1V/V.

C2 ≈ 10/fc uf, qhov twg fc yog qhov txiav tawm zaus (150 Hz rau qhov no).

Tom qab ntawd, qhov tseem ceeb tuaj yeem suav tau raws li qhia hauv kab lus suav nrog daim duab thib ob hauv cov kauj ruam no.

Qhov txiaj ntsig kawg uas tau siv los tso rau hauv cov txheej txheem saum toj no yog:

C2 = 66 nF

C1 = 33 nF

R1 = 22.47 kOhm

R2 = 22.56 kOhm

Kauj Ruam 4: Kev npaj ua LabVIEW

Tsuas yog cov ntaub ntawv xav tau rau ntu no ntawm kev sau ECG yog lub khoos phis tawj Windows nruab nrog 64-ntsis theej ntawm LabVIEW thiab Lub Tebchaws Cov Khoom Siv Teeb Meem Teeb Pom Kev Zoo () nrog rau ib qho qauv siv. Daim duab thaiv kev ua haujlwm hauv LabVIEW yuav tsum tau tsim ua raws li hauv qab no. Pib los ntawm kev qhib qhov Tsis Txaus Siab Ua Haujlwm Daim Duab.

Ntxig rau DAQ Assistant thaiv thiab kho qhov teeb tsa rau hauv qab no:

Ntsuas: Analog → Voltage

Hom: RSE

Sampling: Sampling Nruam

Cov Qauv Sau: 2500

Sampling Tus Nqi: 1000 / sec

Tso tawm cov ntaub ntawv sau ua kab ke mus rau daim duab duab. Tsis tas li ntawd, xam tus nqi siab tshaj ntawm cov ntaub ntawv xov xwm tam sim no. Muab tus nqi siab tshaj plaws ntawm nthwv dej los ntawm tus nqi xws li.8 los tsim lub hauv paus rau qhov pom kom pom siab, qhov txiaj ntsig no tuaj yeem hloov kho raws qib suab nrov hauv lub teeb liab. Pub hauv cov khoom ntawm cov kauj ruam dhau los raws li qhov pib thiab cov khoom siv hluav taws xob nyoos raws li cov ntaub ntawv rau "Peak Detection" muaj nuj nqi. Tom ntej no, coj mus rau "Qhov Chaw" cov txiaj ntsig ntawm qhov siab tshaj plaws nrhiav kom tau thiab rho tawm thawj thiab qhov thib ob qhov tseem ceeb. Qhov no sawv cev qhov sib txawv ntawm qhov ntsuas qhov tseem ceeb ntawm ob qhov siab tshaj hauv thawj kab. Qhov no tuaj yeem hloov pauv mus rau lub sijhawm sib txawv los ntawm kev faib tus nqi los ntawm tus qauv piv txwv, piv txwv li qhov no yog 1000 /sec. Thaum kawg, siv qhov thim rov qab ntawm tus nqi no (muab Hz) thiab sib tw los ntawm 60 kom tau txais lub plawv dhia hauv ntaus ib feeb BPM. Daim duab kab thaiv zaum kawg rau qhov no yuav tsum zoo ib yam li daim duab taub hau rau theem no.

Kauj Ruam 5: Kev Ua Haujlwm Tag Nrho

Tam sim no tias txhua yam khoom tau tsim ua tus kheej, nws yog lub sijhawm los muab cov khw ua ke. Qhov no tuaj yeem ua tiav los ntawm kev xaim hluav taws xob tso tawm ntawm ib ntu mus rau cov lus qhia ntawm ntu ntu hauv qab no. Cov theem yuav tsum tau txuas rau hauv tib qhov kev txiav txim uas lawv tshwm sim hauv Phau Ntawv Qhia no. Rau theem kawg, ButterWorth lim, nws cov tswv yim yuav tsum txuas nrog rau ib ntawm ob qhov kev coj ua ntawm cov tswv yim ntawm lub teeb liab lub rooj tswj hwm. Lwm cov hlau lead los ntawm cov qauv no yuav tsum tau txuas nrog cov kab hluav taws xob ib puag ncig.

Rau qhov ntsuas qhov ntsuas, nws ob txoj hauv kev yuav tsum tau txuas rau ib qho ECG/EKG electrode. Qhov no tau ua tiav tau yooj yim nrog kev siv ob daim yeeb yaj kiab. Tom qab ntawd, tso ib qho hluav taws xob ntawm txhua lub dab teg. Ua kom ntseeg tau tias txhua ntu ntawm kev sib txuas tau txuas nrog thiab tias LabVIEW VI tau ua haujlwm thiab lub kaw lus yuav tsum tau nthuav tawm cov duab yoj hauv lub qhov rai LabVIEW.

Cov zis yuav tsum zoo ib yam li daim duab thib ob uas tau muab hauv theem no. Yog tias nws tsis zoo ib yam, qhov txiaj ntsig ntawm koj lub Circuit Court yuav xav tau hloov kho. Ib qho teeb meem tshwm sim yog tias lub hauv paus lim dej yuav tsis nyob ncaj qha ntawm 60 Hz thiab tej zaum yuav me ntsis rau siab/qis. Qhov no tuaj yeem raug sim los ntawm kev tsim cov phiaj xwm rau lub lim. Qhov zoo tshaj plaws, lub ntsej muag lim yuav muaj tsawg kawg 20 dB attenuation ntawm 60 Hz. Nws kuj tseem yuav muaj txiaj ntsig los tshuaj xyuas tias koj lub zog hauv nroog tau muab los ntawm 60 Hz. Nws tsis yog qhov tsis yooj yim rau qee thaj chaw kom muaj 50 Hz AC cov khoom siv, qhov no yuav xav tau kom nyob nruab nrab qhov ntsuas qhov ntsuas ib puag ncig tus nqi no.