What is the function of the filter in EEG signal processing?

The function of the filter in EEG signal processing is to eliminate frequencies outside of the range of interest. In EEG, the electrical activity of the brain produces signals across a wide range of frequencies, but not all of these frequencies are relevant for every analysis. Filters can be set to focus on specific frequency bands, such as delta, theta, alpha, beta, and gamma waves, which correspond to different states of brain activity.

By eliminating unwanted frequencies, filters help to reduce noise and artifacts that can obscure the meaningful brain signals. This creates a clearer, more interpretable dataset, allowing clinicians and researchers to focus on the specific brain activity they wish to study. Filtering improves the overall signal quality and facilitates more accurate analysis and interpretation of the EEG data.