Filtering PPG signal using Latis-pro.

[imane tech]

Hello Community!
I'm working on filtering a signal related to My heartbeat sensor, I used the FFT method in Latis-pro to see which frequencies I need to remove! You'll find down below the results that I had! I Found on the spectrum a weird result, a signal that has a frequency = 0 Hz.

 

[rjenkinsgb]

I think the biggest problem is that the signal resolution is so low.
If you cannot increase the signal level, can you reduce the ADC min & max references so they are nearer to the range the signal uses? That should give much better detail.

It's not obvious what the frequency or amplitude scales of the FFT are. There is a large DC (0Hz) component as it stays at the same few levels for many samples. It may be again that the FFT needs a wider input range to give a reasonable output.