Automated ECG: Kev nthuav dav thiab lim Simulations Siv LTspice: 5 Cov Kauj Ruam

2024 Tus sau: John Day | [email protected]. Kawg hloov kho: 2024-01-30 09:24

Nov yog daim duab ntawm lub cuab yeej kawg uas koj yuav tsim thiab sib tham tob tob txog txhua feem. Kuj piav qhia txog kev suav rau txhua theem.

Cov duab qhia pom daim duab thaiv rau lub cuab yeej no

Txoj Kev thiab Cov Khoom:

Lub hom phiaj ntawm txoj haujlwm no yog txhawm rau txhim kho lub teeb liab tau txais lub cuab yeej txhawm rau txhawm rau ua tus yam ntxwv tshwj xeeb ntawm lub teeb liab/khaws cov ntaub ntawv cuam tshuam ntawm lub teeb liab. Tshwj xeeb tshaj yog, kev siv lub tshuab ECG. Daim duab thaiv kab lus pom hauv daim duab 3 qhia txog cov tswv yim npaj rau lub cuab yeej. Cov cuab yeej yuav tau txais lub teeb liab lom los ntawm lub tshuab hluav taws xob thiab tom qab ntawd ua kom nws siv lub suab nrov nrog qhov nce ntawm 1000. Qhov kev nthuav dav no yog qhov tsim nyog vim tias lub teeb liab lom yuav tsawg dua ntawm 5mV uas me me thiab tuaj yeem nyuaj rau txhais [5]. Tom qab ntawd, lub suab nrov yuav raug txo qis siv lub lim lim lim kom tau txais qhov xav tau ntau zaus rau lub teeb liab, 0.5-150 Hz, thiab tom qab ntawd thais yuav ua raws li txhawm rau tshem tawm cov suab ib puag ncig ib puag ncig los ntawm cov kab hluav taws xob pom ib puag ncig 50-60 Hz [11]. Thaum kawg, lub teeb liab yuav tsum tau hloov pauv mus rau digital kom nws tuaj yeem txhais tau siv lub khoos phis tawj thiab qhov no ua tiav nrog kev sib piv rau digital hloov pauv. Hauv txoj kev tshawb fawb no txawm li cas los xij, kev tsom mus rau feem ntau yog nyob ntawm lub suab nrov, lim bandpass, thiab lub ntsej muag lim.

Lub tshuab ua kom nrov nrov, bandpass lim, thiab lub hauv paus lim tau tsim thiab simulated siv LTSpice. Txhua ntu tau tsim thawj zaug cais thiab kuaj xyuas kom paub tseeb tias lawv ua tau zoo thiab tom qab ntawv sib koom ua ib qho txheej txheem zaum kawg. Lub suab nrov, uas tuaj yeem pom hauv daim duab 4, tau tsim thiab ua los ntawm cov cuab yeej siv suab nrov. Ib qho cuab yeej siv suab nrov feem ntau siv hauv ECGs, ntsuas kub, thiab txawm tias lub tswb ntsuas hluav taws xob vim tias nws tuaj yeem ua kom lub suab qis qis heev thaum tsis lees txais lub suab nrov ntau. Nws kuj tseem yooj yim heev los hloov kho txhawm rau kho qhov xav tau qhov xav tau [6]. Qhov xav tau nce rau Circuit yog 1000 thiab qhov no tau xaiv txij li cov tswv yim los ntawm cov hluav taws xob yuav yog AC teeb liab tsawg dua 5 mV [5] thiab yuav tsum tau ua kom nrov nrov txhawm rau ua kom cov ntaub ntawv yooj yim txhais. Txhawm rau kom tau txais txiaj ntsig ntawm 1000, sib npaug (1) GAIN = (1+ (R2+R4)/R1) (R6/R3) tau siv uas yog li ntawd tau txais GAIN = (1+ (5000Ω+5000Ω)/101.01Ω) (1000Ω/100Ω) = 1000. Txhawm rau kom paub tseeb qhov raug ntawm qhov ua kom tiav tau tiav, kev sim ncua sijhawm tau ua tiav siv LTspice.

Theem thib ob yog lub lim lim bandpass. Lub lim dej no tuaj yeem pom hauv daim duab 5 thiab suav nrog qhov qis qis thiab tom qab ntawd lub siab lim nrog lub tshuab ua haujlwm ua haujlwm nyob nruab nrab los tiv thaiv cov ntxaij lim dej los ntawm kev tshem tawm ib leeg tawm. Lub hom phiaj ntawm theem no yog tsim cov txheej txheem ntau zaus uas yuav siv tau kom dhau los ntawm lub cuab yeej. Qhov xav tau ntau yam rau lub cuab yeej no yog 0.5 - 150 Hz vim qhov no yog tus qauv ntau yam rau ECG [6]. Txhawm rau ua tiav cov hom phiaj no, sib npaug (2) txiav tawm zaus = 1/(2πRC) tau siv txhawm rau txhawm rau txiav txim siab txiav tawm zaus rau ob qho kev hla siab thiab lim qis hauv bandpass. Txij li qhov qis kawg ntawm qhov xav tau yog 0.5 Hz, lub siab dhau lim lim resistor thiab tus nqi hluav taws xob tau suav los ua 0.5 Hz = 1/(2π*1000Ω*318.83µF) thiab nrog qhov kawg xav tau 150 Hz, qhov qis dhau lim lim resistor thiab tus nqi hluav taws xob tau suav ua 150 Hz = 1/(2π*1000Ω*1.061µF). Txhawm rau lees paub tias qhov ntau zaus raug tau ua tiav, AC cheb tau khiav siv LTspice.

Qhov thib peb thiab zaum kawg simulated theem yog lub ntsej muag lim thiab tuaj yeem pom hauv daim duab 6. Lub ntsej muag lim dej ua haujlwm txhais tau tias tshem tawm cov suab tsis xav tau uas tshwm sim nyob hauv nruab nrab ntawm qhov xav tau ntau yam tsim los ntawm bandpass. Lub hom phiaj zaus hauv qhov no yog 60 Hz vim tias yog tus qauv siv hluav taws xob ntau zaus hauv Tebchaws Meskas thiab ua rau cuam tshuam yog tias tsis cuam tshuam nrog [7]. Cov lim dej xaiv tau txhawm rau txhawm rau txhawm rau cuam tshuam qhov cuam tshuam no yog ntxaib t thais lim nrog ob lub op amps thiab qhov faib hluav taws xob. Qhov no yuav tso cai rau lub teeb liab kom tsis tsuas yog lim tawm lub teeb liab ncaj qha ntawm lub hom phiaj nquag tab sis kuj qhia tawm qhov kev tawm tswv yim sib txawv rau hauv qhov system, qhov hloov pauv tau qhov ua tau zoo Q, thiab cov txiaj ntsig sib txawv ua tsaug rau qhov faib hluav taws xob thiab yog li ua qhov lim dej no hloov pauv ib passive [8]. Cov xwm txheej ntxiv no txawm li cas los xij feem ntau tsis muaj kev cuam tshuam hauv thawj qhov kev sim tab sis yuav raug kov rau hauv kev ua haujlwm yav tom ntej thiab yuav txhim kho txoj haujlwm tom qab li cas. Txhawm rau txiav txim siab qhov nruab nrab ntawm qhov tsis lees paub zaus, kab zauv (3) qhov chaw tsis lees paub zaus = 1/(2π)*√ (1/(C2*C3*R5*(R3+R4))) = 1/(2π)* √ (1/[(0.1*10^-6µF)*(0.1*10^-6µF) (15000Ω)*(26525Ω +26525Ω)]) = 56.420 Hz tau ua haujlwm. Txhawm rau kom paub tseeb tias qhov ua yuam kev tsis raug tau ua tiav, AC cheb tau khiav siv LTspice.

Thaum kawg, tom qab txhua qib tau sim cais, peb theem tau sib koom ua ke raws li pom hauv Daim Duab 7. Nws tseem yuav tsum tau sau tseg tias txhua qhov op amps tau muab nrog +15V thiab -15V DC fais fab mov txhawm rau tso cai rau ua kom muaj zog ntau ntxiv tshwm sim thaum tsim nyog. Tom qab ntawd ob qho kev sim hla thiab AC cheb tau ua tiav ntawm qhov ua tiav.

Cov txiaj ntsig:

Cov duab kab rau txhua theem tuaj yeem pom ncaj qha hauv nws cov theem sib txawv hauv Daim Duab hauv ntu ntxiv. Rau thawj theem, qhov ntsuas qhov ntsuas qhov ntsuas tau hloov pauv ntawm lub Circuit Court txhawm rau txhawm rau ntsuas kom paub tseeb tias qhov nce rau lub suab nrov yog 1000. Qhov ntsuas tau khiav los ntawm 1 - 1.25 vib nas this nrog lub sijhawm siab tshaj plaws ntawm 0.05. Cov khoom siv hluav taws xob yog AC sine wave nrog qhov dav ntawm 0.005 V thiab zaus ntawm 50 Hz. Lub hom phiaj tau nce yog 1000 thiab zoo li pom hauv daim duab 4, txij li Vout (txoj kab nkhaus ntsuab) muaj qhov dav ntawm 5V. Qhov simulated nce tau suav los ua, nce = Vout/Vin = 5V/0.005V = 1000. Yog li, feem pua yuam kev rau theem no yog 0%. 0.005V tau xaiv los ua cov tswv yim rau ntu no vim nws yuav cuam tshuam nrog cov tswv yim tau txais los ntawm cov hluav taws xob raws li tau hais hauv ntu txheej txheem.

Theem thib ob, bandpass lim, muaj lub hom phiaj ntau ntawm 0.5 - 150 Hz. Txhawm rau ntsuas cov lim thiab ua kom ntseeg tau qhov sib npaug, ib xyoo caum, AC cheb tau khiav nrog 100 cov ntsiab lus ib xyoo kaum xyoo los ntawm 0.01 - 1000 Hz. Daim duab 5 qhia pom cov txiaj ntsig los ntawm AC cheb thiab lees paub tias ntau zaus ntawm 0.5 txog 150 Hz tau ua tiav vim qhov siab tshaj plaws rho tawm 3 dB muab qhov txiav tawm ntau zaus. Txoj kev no yog qhia hauv kab ntawv.

Theem thib peb, lub ntsej muag lim, tau tsim los tshem tawm cov suab nrov nyob ib puag ncig 60 Hz. Qhov suav nruab nrab ntawm qhov tsis lees paub zaus yog ~ 56 Hz. Txhawm rau lees paub qhov no, ib xyoo caum, AC cheb tau khiav nrog 100 cov ntsiab lus ib xyoo caum los ntawm 0.01 - 1000 Hz. Daim duab 6 qhia pom cov txiaj ntsig los ntawm AC cheb thiab qhia txog qhov nruab nrab ntawm qhov tsis lees paub zaus ~ 56-59 Hz. Feem pua yuam kev rau ntu no yuav yog 4.16 %.

Tom qab lees paub tias txhua tus tib neeg tau ua haujlwm, peb theem tom qab tau sib sau ua ke raws li pom hauv daim duab 7. Tom qab ntawd qhov kev ntsuas ib ntus tau khiav los tshuaj xyuas qhov ua haujlwm ntawm Circuit thiab qhov ntsuas tau khiav ntawm 1 - 1.25 vib nas this nrog lub sijhawm siab tshaj plaws ntawm 0.05 nrog muab qhov hluav taws xob ntawm AC sine wave nrog qhov dav ntawm 0.005 V thiab zaus ntawm 50 Hz. Qhov tshwm sim yog thawj daim duab hauv daim duab 7 qhia Vout3 (liab), qhov tso tawm ntawm tag nrho cov Circuit Court, yog 3.865 V thiab yog li ntawd ua qhov nce = 3.865V/0.005V = 773. Qhov no txawv txav ntau dua li qhov kev xav tau ntawm 1000 thiab muab qhov yuam kev ntawm 22.7%. Tom qab qhov kev xeem dhau mus, ib xyoo caum, AC cheb tau khiav nrog 100 cov ntsiab lus ib xyoo twg los ntawm 0.01 - 1000 Hz thiab tsim cov duab thib ob hauv daim duab 7. Daim duab no qhia txog cov txiaj ntsig tau npaj tseg thiab qhia cov ntxaij lim dej ua haujlwm ua ke los tsim cov lim uas lees txais zaus ntawm 0.5-150 Hz nrog qhov chaw tsis lees paub los ntawm 57.5-58.8 Hz.

Sib npaug:

(1) - nce ntawm cov cuab yeej siv suab nrov [6], cov neeg tawm tsam txheeb ze rau cov uas pom hauv daim duab 4.

(2) - txiav tawm zaus rau qhov qis/siab dhau lim

(3) - rau ntxaib t notch lim [8], resistors txheeb ze rau cov uas pom hauv daim duab 6.

Kauj Ruam 1: Kev Ntsuas Hluav Taws Xob

Theem 1: cov cuab yeej siv suab nrov

equation - GAIN = (1+ (R2+R4)/R1) (R6/R3)

Kauj ruam 2: Bandpass

theem 2: bandpass lim

qhov sib npaug: txiav tawm zaus = 1/2πRC

Kauj Ruam 3: Kauj Ruam 3: Ntxuav Lim

theem 3: Ntxaib T Notch lim

equation - qhov chaw tsis lees paub zaus = 1/2π √ (1/(C_2 C_3 R_5 (R_3+R_4)))

Kauj Ruam 4: Cov Txheej Txheem Zaum Kawg ntawm Txhua Kauj Ruam Ua Ke

Schematic kawg nrog cheb ac thiab ncua nkhaus

Kauj Ruam 5: Kev Sib Tham Ntawm Ntaus Ntawv

Sib tham:

Qhov tshwm sim los ntawm cov kev ntsuas ua tau hais los saum toj no tau mus raws li qhov xav tau ntawm Circuit Court tag nrho. Txawm hais tias qhov kev hloov pauv tsis zoo tag nrho thiab lub teeb liab poob qis me ntsis ntxiv nws tau hla lub Circuit Court (uas tuaj yeem pom hauv daim duab 7, kab 1 uas qhov teeb liab tau nce los ntawm 0.005V txog 5V tom qab thawj theem thiab tom qab ntawd poob mus rau 4V tom qab qhov thib ob thiab tom qab ntawd 3.865V tom qab theem kawg), bandpass thiab thais lim tau ua haujlwm raws li qhov xav tau thiab tsim tawm ntau zaus ntawm 0.5-150 Hz nrog tshem tawm zaus txog 57.5-58.8 Hz.

Tom qab tsim cov kev ntsuas rau kuv lub Circuit Court, tom qab ntawd kuv muab piv rau ob lwm ECGs. Kev sib piv ncaj qha nrog tsuas yog cov lej tuaj yeem pom hauv Table 1. Muaj peb qhov tseem ceeb coj mus thaum muab kuv cov ntaub ntawv piv rau lwm qhov chaw ntawm cov ntaub ntawv. Thawj yog tias qhov kev hloov pauv hauv kuv qhov kev sib tw tau qis dua li ob qhov kuv tau sib piv ib yam. Ob qho ntawm cov ntaub ntawv cov ntaub ntawv cov khoom siv hluav taws xob tau ua tiav qhov kev nthuav dav ntawm 1000 thiab hauv Gawali's ECG [9], lub teeb liab tseem tau txuas ntxiv los ntawm qhov tseem ceeb ntawm 147 hauv theem lim. Yog li ntawd, txawm hais tias lub teeb liab hauv kuv lub xov tooj tau nthuav dav los ntawm 773 (22.7% yuam kev thaum piv rau tus qauv ua kom nrov) thiab pom tias txaus kom tuaj yeem txhais cov teeb liab nkag los ntawm lub tshuab hluav taws xob [6], nws tseem tsawg dua qhov piv rau tus qauv ua kom nrov yog 1000. Yog tias kev ua kom lub suab nrov tau ua tiav hauv kuv lub Circuit Court, kev ua kom nrov hauv cov cuab yeej siv suab nrov yuav tsum tau nce mus rau qhov tseem ceeb ntau dua 1000 yog li ntawd thaum cov txiaj ntsig tau nqis qis dua tom qab dhau los ntawm txhua theem lim hauv kuv qhov Circuit, nws tseem muaj qhov nce tsawg kawg 1000 lossis cov ntxaij lim dej yuav tsum tau hloov kho txhawm rau tiv thaiv qhov hluav taws xob poob qis ntau dua los ntawm qhov tshwm sim.

Qhov loj thib ob nqa mus yog tias tag nrho peb qhov kev sib tw tau muaj ntau zaus zoo ib yam. Gawali's [9] muaj qhov sib txawv ntawm 0.5-150 Hz thaum Goa [10] muaj qhov dav me ntsis ntawm 0.05-159 Hz. Goa's Circuit tau muaj qhov sib txawv me me no vim tias ntau qhov zoo dua daim npav nrhiav cov ntaub ntawv uas tau siv hauv lawv teeb tsa.

Qhov kev nqa loj kawg yog qhov sib txawv hauv qhov nruab nrab ntawm kev tsis lees paub ua tiav los ntawm cov ntxaij lim dej hauv txhua qhov Circuit Court. Gao's thiab kuv qhov kev sib tw ob leeg muaj lub hom phiaj ntawm 60 Hz txhawm rau txhawm rau txwv txoj kab suab nrov ua rau cov kab hluav taws xob thaum Gawali tau teeb tsa rau 50 Hz. Txawm li cas los xij, qhov sib txawv no yog qhov zoo vim nyob ntawm qhov chaw nyob hauv ntiaj teb, cov kab hluav taws xob zaus tuaj yeem yog 50 lossis 60 Hz. Yog li ntawd, kev sib piv ncaj qha tsuas yog ua rau Goa txoj kev siv hluav taws xob vim kev cuam tshuam kab hauv Tebchaws Meskas yog 60 Hz [11]. Qhov feem pua yuam kev yog 3.08%.