Kev Tau Txais, Kev Loj Hlob, thiab Kev Tshawb Fawb Circuit Court ntawm Kev Siv Hluav Taws Xob Hluav Taws Xob: 6 Kauj Ruam

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

Txhawm rau ua kom tiav cov lus qhia no, tsuas yog yam xav tau yog lub khoos phis tawj, siv internet, thiab qee qhov simulation software. Rau lub hom phiaj ntawm kev tsim qauv no, txhua qhov kev sib tw thiab kev sim yuav raug ua haujlwm ntawm LTspice XVII. Qhov kev sim software no muaj cov tsev qiv ntawv ntau dua 1, 000 yam uas ua rau tsim cov khoom siv yooj yim heev. Vim tias cov kab hluav taws xob no yuav dav dav, "UniversalOpAmp2" yuav siv rau txhua qhov piv txwv uas xav tau op-amp. Ib qho ntxiv, txhua qhov op -amp tau siv los ntawm +15V thiab -15V fais fab mov. Cov khoom siv hluav taws xob no tsis yog siv hluav taws xob nkaus xwb tab sis tseem kaw qhov hluav taws xob tso tawm yog tias nws tau mus txog ib qho ntawm ob qho kev tsis txaus ntseeg no.

Kauj Ruam 1: Kev Tsim Kho Cov Khoom Siv Hluav Taws Xob

Tom qab tau txais lub teeb liab, nws yuav tsum tau nthuav dav los ua cov lej thiab lim ntawm nws. Txog electrocardiograms, txoj kev siv ntau tshaj plaws yog kev siv lub tshuab ua kom nrov nrov. Raws li tau hais los saum toj no, cov cuab yeej siv suab nrov muaj ntau qhov zoo thaum nws los txog rau kev ua kom muaj zog txuas ntxiv, qhov loj tshaj yog qhov tsis muaj kev cuam tshuam ntawm cov tswv yim hluav taws xob. Txhawm rau tsim lub voj voog no, 3 op-amps tau siv ua ke nrog xya tus tiv thaiv, nrog rau rau ntawm tus tiv thaiv sib npaug hauv qhov ntau. Qhov nce ntawm feem ntau cov electrocardiograms yog nyob ib puag ncig 1000x cov teeb liab tawm tswv yim [1]. Qhov sib npaug rau qhov nce ntawm qhov ntsuas qhov ntsuas yog raws li hauv qab no: Tau = 1 + (2 * R1/R2) * (R7/R6). Rau qhov yooj yim, txhua tus tiv thaiv tau xav tias yog 1000 ohms, tshwj tsis yog rau R2, uas tau txiav txim siab ua 2 ohms. Cov txiaj ntsig no muab qhov nce ntawm 1001 zaug loj dua qhov hluav taws xob nkag. Qhov kev nce no yog txaus los nthuav tawm cov cim tau txais rau kev tshuaj xyuas ntxiv. Txawm li cas los xij, siv cov kab zauv, qhov nce tuaj yeem yog txhua yam uas xav tau rau lawv cov qauv tsim.

Kauj Ruam 2: Band Pass Lim Tsim

Lub lim lim bandpass yog lub lim lim siab thiab lub lim qis dhau ua haujlwm hauv kev sib koom tes feem ntau nrog op-amp los muab qhov uas paub tias yog daim npav hla. Tus passband yog qhov ntau ntawm cov zaus uas tuaj yeem hla thaum txhua lwm tus, saum toj thiab hauv qab, raug tsis lees paub. Cov qauv kev lag luam hais tias tus qauv electrocardiogram yuav tsum muaj daim npav hla ntawm 0.5 Hz txog 150 Hz [2]. Daim npav hla loj no ua kom ntseeg tau tias txhua lub teeb liab hluav taws xob los ntawm lub plawv tau sau tseg thiab tsis muaj ib qho twg raug lim tawm. Ib yam nkaus, daim npav hla no tsis lees txais DC offset uas tuaj yeem cuam tshuam nrog lub teeb liab. Txhawm rau tsim qhov no, tshwj xeeb cov neeg tawm tsam thiab cov khoom siv hluav taws xob yuav tsum raug xaiv kom qhov kev txiav tawm siab dhau yog ntawm 0.5 Hz thiab qhov txiav qis qis qis yog 150 Hz. Kev txiav tawm qhov sib npaug rau ob qhov siab dhau thiab lim qis dhau yog raws li hauv qab no: Fc = 1/(2*pi*RC). Txog kuv qhov kev suav, xaiv tus neeg tawm tsam tus kheej, tom qab siv Equation 4, tus nqi hluav taws xob tau suav. Yog li ntawd, lub siab dhau lim yuav muaj tus tiv thaiv tus nqi ntawm 100, 000 ohms thiab tus nqi capacitor ntawm 3.1831 microfarads. Ib yam nkaus, cov lim qis dhau yuav muaj tus tiv thaiv tus nqi ntawm 100, 000 ohms thiab tus nqi capacitor ntawm 10.61 nano-farads. Daim duab ntawm lub lim lim bandpass nrog cov txiaj ntsig hloov kho tau qhia.

Kauj Ruam 3: Tsim Dej Lim

Lub taub ntim lim yog qhov tseem ceeb qhov sib txawv ntawm cov lim bandpass. Hloov chaw kom muaj tus lej siab ua raws los ntawm qib qis, nws yog qhov qis dua ua raws los ntawm qib siab, yog li ib tus tuaj yeem tuaj yeem tshem tawm ib pab pawg me me ntawm lub suab nrov. Rau qhov ntsuas qhov ntsuas ntawm lub tshuab electrocardiogram, Twin-T thais lim tsim tau siv. Qhov kev tsim no tso cai rau qhov nruab nrab nruab nrab kom raug lim thiab muab qhov ua tau zoo zoo. Hauv qhov no, qhov chaw nruab nrab kom tshem tawm yog ntawm 60 Hz. Siv Qhov Sib Piv 4, tus nqi tiv thaiv tau suav nrog siv tus nqi hluav taws xob muab los ntawm 0.1 microfarads. Kev suav qhov ntsuas tus nqi rau 60 Hz nres band yog 26, 525 ohms. Tom qab ntawd R5 tau suav tias yog ½ ntawm R3 thiab R4. C3 kuj tau suav ua ob npaug tus nqi xaiv rau C1 thiab C2 [3]. Kev xaiv cov neeg tawm tsam tau xaiv rau R1 thiab R2.

Kauj Ruam 4: Kev Sib Txuas Circuit

Siv cov nets, cov khoom siv no tau muab tso ua ke ua ke thiab cov duab ntawm qhov ua tiav Circuit Court yog daim duab. Raws li daim ntawv tshaj tawm los ntawm Springer Science, qhov tau txais txiaj ntsig ntawm ECG Circuit Court yuav tsum nyob ib puag ncig 70 dB thaum tag nrho cov teeb tsa tau teeb tsa [4].

Kauj Ruam 5: Xeem Lub Circuit Court

Thaum txhua lub Cheebtsam tau muab tso rau hauv ib kab, yuav tsum tau siv tus qauv tsim. Kuaj qhov kev sib tw no, ob qho kev hloov pauv ib ntus thiab AC tau ua los txiav txim siab tias txhua yam khoom ua haujlwm tau koom ua ke. Yog tias qhov no tshwm sim, qhov hluav taws xob tso tawm hluav taws xob tseem yuav yog txog 1000x qhov hluav taws xob nkag. Ib yam nkaus, thaum AC cheb tau ua, cov qhab-hla lim bode zaj dab neeg yuav cia siab nrog lub thais ntawm 60 Hz. Saib ntawm cov duab thaij duab, lub voj voog no tuaj yeem ua tiav ob qho ntawm cov hom phiaj ntawd. Lwm qhov kev sim tau pom qhov ua tau zoo ntawm lub taub lim. Txhawm rau ntsuas qhov no, 60 Hz teeb liab tau dhau los ntawm Circuit Court. Raws li daim duab, qhov loj ntawm qhov tso tawm no tsuas yog txog 5x ntau dua li cov tswv yim, piv rau 1000x thaum qhov zaus nyob hauv daim ntawv hla dhau.

Kauj Ruam 6: Cov peev txheej:

[1] “ECG Kev Ntsuas Kev Ntsuas,” Columbia.edu, 2020. https://www.cisl.columbia.edu/kinget_group/student_projects/ECG%20Report/E6001%20ECG%20final%20report.htm (nkag mus rau Kaum Ob Hlis 01, Xyoo 2020).

[2] L. G. Tereshchenko thiab M. E. Josephson, “Cov ntsiab lus nquag thiab yam ntxwv ntawm Ventricular Conduction,” Phau ntawv Journal of electrocardiology, vol. 48, nra. 6, pp. 933–937, 2015, doi: 10.1016/j.jelectrocard.2015.08.034.

[3] “Band Stop Filters hu ua Reject Filters,” Basic Electronics Tutorials, Tsib Hlis 22, 2018.

[4] N. Guler thiab U. Fidan, “Wireless Transmission of ECG signal,” Springer Science, vol. 30, Plaub Hlis 2005, doi: 10.1007/s10916-005-7980-5.