The NL134/5/6 Four Channel Low Pass Filters, second order (two-pole) low-pass with mains frequency Notch reject (NL135/6 only) filter modules. They are ideal partners for the NL820 Isolated Amplifier system. The filter settings have been selected for most electrophysiological protocols but other frequencies can be factory set to order. A rotary switch selects the 14 frequency settings giving repeatability over a wide range with 12dB/octave [40dB/decade] attenuation above the selected frequency value. The ‘WB’ (wide-band) switch position by-passes the filter sections completely (both LP and Notch).

The NL134-5-6 Four Channel Low Pass Filters active Notch filter provides rejection of line frequency [50Hz (NL135) or 60Hz (NL136)] interference when switched in. (No switch is fitted on the NL134).