Notch filter?

[sfo62]

With other EEG equipment, I might run a notch filter at 60 Hz (in North America). But because the Biosemi system is battery operated, I am wondering:

1) Is it necessary with this system?

2) If so, should it be at 60 or 50 Hz?

3) Or should I do it at 60 Hz regardless/in addition to as that's what the other equipment in the room operates at (or its harmonics)?

[Coen]

Applying a notch filter is not necessary because of the combination of active electrodes, battery power supply, and an optic fiber data link (level of mains interference is low enough to make a notch filter superfluous).

Bundle the electrode wires if your still see 50/60 Hz in the data (to minimize the pickup of magnetic interference by wire loops)

Best regards, Coen (BioSemi)