Can I use filtfilt with a Highpass filter?
9 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Philipp Leibner
le 22 Jan 2018
Commenté : Philipp Leibner
le 30 Jan 2018
Hello,
I am wondering if it is okay to use the filtfilt function with a Highpass-Filter since the filtfilt documentation states "Do not use filtfilt with differentiator ..." and a Highpass-Filter has a differentiator-control-element (right?) in it? The problem occurred to me because I discovered that I get very different result using my filter that also has Highpass characteristics.
Best regards Philipp
0 commentaires
Réponse acceptée
Grant Sellers
le 29 Jan 2018
Hello Philipp,
If you look at the code of the filtfilt function, using "edit filtfilt", you will notice a slightly different description for the warning found in the documentation:
"Note that FILTFILT should not be used when the intent of a filter is to modify signal phase, such as differentiators and Hilbert filters. "
The high pass filter, while it has differentiator elements, has a more stable phase response than a pure differentiator, and its end goal is not to phase the signal. High pass filters should still work with this function.
It may make sense that you still get different results when using your filter with filtfilt. Zero-phase filters respond differently, since they are a-causal and because the startup and ending transients are minimized by matching initial conditions.
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Digital Filtering dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!