Biomedical signal processing – ECG

This project’s aim was to build a usable and portable electrocardiograph (ECG) and theorize, simulate and confirm by experimentation an improvement in the value of the amplifier Common Mode Rejection Ratio (CMRR) by re-calibrating resistance in the patient cables – the cables that connect the patient to the instrument. It was part of a bigger project to improve the performance of many biomedical instruments, conducted by the Biomedical Engineering department in the hospital at the University Campus Bio-Medico di Roma, in Rome, Italy.


  • Built a ECG working prototype both on breadboard and stripboard.
  • Theoretically demonstrated the results I obtained both by simulation and experimentation.
  • Found a way to considerably improve CMRR.
improved signal

non-improved signal

Overcame impediments
  • Learning to use the electronic and software tools I was provided with. I overcame this obstacle using documentation, tutorials and comparing my understanding with my colleagues and supervisor.
  • Reduction of the 50Hz noise until the Signal Noise Ratio (SNR) was less than 1. I overcame this obstacle by researching and testing different solutions to the problem and applying the one that gave the best results.
Skills acquired or improved:

Ni Multisim, Electronics, Mathematics.