EC06 · Sem 6 · Biomedical signal processing

Biomedical signal filtering (synthetic ECG)

Aim: Clean a noisy ECG-like waveform with a low-pass filter.

🧪 Live simulation🧊 Real-time 3D bench⚠ Simulated values, not physical measurements

🔬 Virtual lab

Starting the lab…

📘 Theory

ECG features (P, QRS, T) live mostly below 40 Hz; muscle and electrode noise is broadband. A low-pass filter around 40 Hz keeps the shape while removing noise. This signal is synthetic and for teaching only.

heart rate (bpm) = 60 / RR interval (s)

🧰 Apparatus (virtual)

Synthetic ECG generator (72 bpm)
noise source
IIR filter

📝 Procedure

Select the ECG signal and add noise
Apply an IIR low-pass at 40 Hz
Compare the QRS peaks before and after
Lower the cut-off too far and see the QRS distort

Observations and result (kept on this device)

🎤 Viva questions

Why is a 50 Hz notch filter common in ECG machines

Mains interference is strong at 50 Hz.

What happens to the QRS if the cut-off is too low

It becomes wider and smaller.

🛡️ Safety

Virtual lab. With real RF equipment, respect exposure limits, never transmit without a licence, and keep antennas away from people.