Analisis dan Eksperimen Rangkaian Biopotential Amplifier pada Akuisisi Sinyal Elektrokardiogram (EKG)

Azami Muhammad Farraz, Ir. Prapto Nugroho, ST, M.Eng., D.Eng., IPM. ; Ir. Sigit Basuki Wibowo, ST, M.Eng., Ph.D., IPM.

2023 | Skripsi | S1 TEKNIK BIOMEDIS

Pada tugas akhir ini, alat yang dirancang merupakan sebuah biopotential amplifier yang mampu mengimplifikasi salah satu sinyal biopotensial yaitu EKG serta rangka- ian filter aktif yang berfungsi sebagai peredam derau serta melakukan penguatan akhir pada sinyal. Rancangan biopotential amplifier ini dibangun dengan memanfaatkan IC INA128 yang merupakan jenis IC penguat instrumentasi. Pengujian rangkaian dilakukan dengan metode simulasi dan eksperimen pada rangkaian biopotential amplifier. Simulasi dan eksperimen rangkaian dilakukan menggunakan software LTSpice beserta pembuatan komponen hardware pada PCB yang kemudian hasil sinyal analog akan dipantau dan dianalisis melalui osiloskop di laboratorium. Adapun untuk, nilai yang diamati adalah gain, CMRR, serta bandwidth.

Dari hasil pengujian dan analisis yang telah dilakukan, didapatkan nilai spesifikasi pada simulasi adalah rangkaian memiliki nilai gain 2088, 152.6dB CMRR, serta 0.478 - 39.81Hz bandiwdth. Lalu pada pengujian perangkat hardware rangkaian memiliki nilai gain rangkaian mencapai 2080, 90.18dB CMRR, serta bandwidth di rentang 0.58-40.6 Hz. sistem penguat ini dapat berjalan dengan cukup baik dan telah memenuhi spesifikasi dengan nilai gain rangkaian mencapai 2080 V/V, 90.18dB CMRR, serta bandwidth di rentang 0.58-40.6 Hz.

Penelitian ini diharapkan dapat berguna untuk pengembangan purwarupa biopotential amplifier yang digunakan pada akuisisi sinyal EKG maupun biopotensial lainnya. 

Biopotential observation is a common process used to measure human electrical activity by utilizing electrodes that function as transducers to detect changes in electrical potential. Signal acquisition is necessary for biopotential observation, and one such acquisition involves the Electrocardiogram (ECG) signal. ECG serves as a primary diagnostic tool for identifying and monitoring various heart disorders. A challenge in this process is that the signals produced by heart activity have varying amplitudes and contain various types of noise within specific frequency ranges that can disrupt the biopotential signal acquisition process. Therefore, the biopotential signal acquisition process requires amplification as an output signal booster for subsequent use in signal observation stages, such as signal processing. In this final project, the designed device is a biopotential amplifier capable of amplifying one of the biopotential signals, namely the EKG, and an active filter circuit that acts as a noise suppressor and provides final amplification to the signal. The biopotential amplifier design is constructed using the INA128 IC, which is an instrumentation amplifier IC. Circuit testing is performed through simulation and experimentation on the biopotential amplifier circuit. Circuit simulation and expe- experimentation is conducted using LTSpice software, along with the creation of hardware components on a PCB, and the analog signal results are then monitored and analyzed through an oscilloscope in the laboratory. The observed values include gain, Common- Mode Rejection Ratio (CMRR), and bandwidth. From the conducted testing and analysis, simulation results indicate that the circuit has a gain value of 2088, a CMRR of 152.6dB, and a bandwidth of 0.478 - 39.81Hz. Hardware testing of the circuit yields a gain value of 2080, a CMRR of 90.18dB, and a bandwidth in the range of 0.58-40.6Hz. The amplifier system operates sufficiently well and meets specifications, with a circuit gain of 2080 V/V, a CMRR of 90.18dB, and a bandwidth in the range of 0.58-40.6Hz. This research is expected to be beneficial for the development of prototype biopotential amplifiers used in the acquisition of EKG and other biopotential signals. 

Kata Kunci : Biopotential amplifier, Biopotensial, Elektrokardiogram (EKG)