Analiza biopotencialnega ojačevalnika za zajem elektrokardiograma

KARAČIĆ, KARLO (author), Kramar, Peter (mentor)

Elektrokardiografija je pogosto uporabljen neboleč postopek, ki zajema električno aktivnost srca, z nameščenimi elektrodami na površini kože merjenca. Tako zajetemu signalu rečemo elektrokardiogram. Vsak utrip srca v normalnem elektrokardiogramu je predstavljen z zaporedjem petih značilnih segmentov P, Q, ,R, S in T, ki se periodično ponavljajo. Osnovni namen elektrokardiografije je spremljanje delovanja srca. Vendar se v medicini uporablja tudi za diagnosticiranje kardiovaskularnih bolezni. Predmet našega raziskovanja je biopotencialni ojačevalnik z dvema vhodoma, ki je del laboratorijskih vaj in ga študentje sestavijo na testni plošči. Med izvedbo vaj so se jim pojavljale težave, ki niso imele pojasnjenega vzroka. Namen moje diplomske naloge je bil, da vezje celostno analiziram in na podlagi rezultatov podam priporočila za izboljšavo vezja. Analizo smo naredili z merjenjem vhodne in izhodne napetosti biopotencialnega ojačevalnika, rezultate pa prikazal z Bodejevim diagramom in razmerjem med signalom in šumom (SNR). Signala elektrokardiograma smo primerjali s potekom elektrokardiograma zajetim s komercialnim biopotencialnim ojačevalnikom Biopac. Po pregledu rezultatov smo ugotovili, da je vpliv testne plošče prevelik, da bi lahko smiselno ocenili vplive ostalih parametrov. Zato smo predlagali, da bi bilo smiselno izvesti meritve na biopotencialnem ojačevalniku, ki bi bil narejen na tiskanem vezju. Tako bi lahko bistveno boljše ocenili vplive parametrov na stabilnost biopotencialnega ojačevalnika in kvaliteto zajetega elektrokardiograma.

• Language: Slovenian
• Keywords: elektrokardiogram, elektrokardiografija, biopotencialni ojačevalnik, Bodejev diagram
• Work type: Undergraduate thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2015
• PID: 20.500.12556/RUL-73948
• Publication date in RUL: 07.12.2015

Secondary language

• Language: English

Abstract

Electrocardiography is a commonly used, noninvasive procedure for recording electrical changes in the heart. The record, which is called an electrocardiogram, shows the series of waves that relate to the electrical impulses which occur during each beat of the heart. The waves in a normal record are named P, Q, R, S, and T and follows in alphabetical order. The primary purpose of electrocardiography is monitoring of cardiac function. However, in the field it will also be used to diagnose cardiovascular disease. The subject of our research is biopotential amplifier with two inputs, which is part of the laboratory exercises that students assemble on the breadboard. During the execution of the exercises they have encountered a problem that did not have a clarified cause. The aim of my thesis was to analyze the biopotential amplifier and on the basis of the results to give recommendations for improvement of the circuit. Analyses were done by measuring the input and output voltages of biopotential amplifier, the results were shown on the Bode plot and signal-to-noise ratio (SNR). Electrocardiogram signal was compared with commercial biopotential amplifier, Biopac. The results show that the impact of the breadboard is too high to be able to reasonably assess the effects of other parameters. Therefore for I suggest that it would be sensible to carry out measurements taken on a printed circuit board, because we could significantly better assess the effects of parameters on the stability of biopotential amplifier and the quality of measured electrocardiogram signal.

• Keywords: electrocardiogram, electrocardiography, biopotential amplifier, Bode plot