| Display filters in ASA 4.8 |
| The filter type of the display filter which is also known as a view filter or on-the-fly filter has been improved in regard to previous versions. This filter is set in the EEG toolbar, montages or in the channel list. In the previous versions the display filter type was infinite impulse response ((IIR) with Butterworth filter. This, so called causal kind of filter type has the disadvantage of introducing a phase-shift in the filter data. The new filter type used is a 4th order non-causal Butterworth filter which produces a zero phase-shift. Because of the implementation of this different filter type, ASA users might observe a change in the phases of EEG / ERP components compared to similar display filter settings in previous ASA versions. This filter feature has been already introduced in the ASA software with version 4.6.0.3. |
|