Can anyone help us by describing the input circuitry on the NI-9209 voltage DAQ module?
The datasheet defines input span and mentions 50/60Hx noise rejection and alias rejection, but doesn't state how any of this is achieved.
The two operating modes 'High-Resolution' and 'High-Speed' have different alias rejection levels and different sample rates. If you interpolate between the two points (rejection level / sample rates) you obtain a attenuation rate of about -6dB per octave (which would imply a single pole filter) and extrapolating backwards you reach the -3dB point at about 5Hz.
So the question is, does the NI-9209 have a single pole filter at 5Hz ...?
... and if so, are there more filters, in-line, to give added attenuation at 50/60Hz?
If neither of the above is correct, is anyone able to say what the input filtering actually looks like?
