<![CDATA[The Electrocardiogram (ECG) signal is an important biomedical signal that is used to record the electrical activity of the heart. In the ECG signal acquisition process, high-frequency noise contamination often occurs that can disrupt clinical analysis. This research designs and tests an active Low Pass Filter (LPF) circuit based on the IC LM358 with a 100 nF capacitor to reduce noise in the ECG signal. Testing was performed by varying the resistor values to 100 Ω, 680 Ω, 1 kΩ, 10 kΩ, 100 kΩ, and 1 MΩ to obtain different cut-off frequencies for each configuration. The test results show that the larger the resistor value, the lower the cut-off frequency and attenuation at high frequencies, is better. The 1 MΩ resistor yields a cut-off frequency of about 1.59 Hz with the steepest output voltage drop from 0.25 V at 5 Hz to 0.055 V at 100 Hz. The 10 kΩ resistor configuration is considered the most optimal for ECG applications because it yields a cut-off frequency of ≈ 159 Hz that still covers the entire bandwidth diagnostic ECG signal (0.5–150 Hz) with characteristics of high-frequency attenuation that is good.]]>
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