48. Two types of recording
• Bipolar – both the electrodes are at active site
• Unipolar/Referential – one electrode is active and the other is
indifferent kept at ear lobe.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58. Filters in EEG
A notch filter is used to reject the 60
Hz or 50 Hz power line noise. The
notch is a very selective filter with a
very high rejection just for a tiny
frequency band around the selected
frequency. It will not attenuate other
frequencies which belong to the EEG
signal.
A High-pass filter (filtering out
low frequencies).
• A low pass filter is needed to
reject noise at (higher
frequencies) than the EEG
signals.
