search

gkasten / drrickorang

Dr. Rick O'Rang
72 stars 39 forks source link

DC offset should get blocked #22

Open philburk opened 6 years ago

philburk commented 6 years ago

Some devices have an initial severe DC offset that distorts the measurement. This can confuse the auto-correlation calculation. The DC offset usually dies down after 50 - 500 msec.

We should detect DC offset and wait for it to die down. If the DC offset is too severe then we should reject the measurement so that the DC offset problem can be addressed.

We could also add a DC blocker on the input to the auto-correlator to improve the auto-correlation result.

https://www.dsprelated.com/freebooks/filters/DC_Blocker.html

gkasten commented 6 years ago

Good suggestion. When we do implement, let's also provide a way to see/report the original DC offset as that kind of thing could also cause a plop in recording and it might be good to know that it is happening, how severe it is, how long it goes on for, etc.