The raw signal is first processed for removing drift from the signals. Therefore, a high-pass filter was implemented before the actual algorithm. To ensure proper heart-beat recognition for detecting the pulse amplitude, a minimum sampling time off 4 seconds was found to be necessary for averaging the amplitudes over multiple heartbeats. Even with an unusually low heart rate of 30 beats per minute, still, two periods could be averaged for analysis. Sampling inaccuracies were filtered out with a low pass filter, configured with a cut-off frequency below the sampling frequency