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This article discusses design considerations relative to phase angles and time delays.

The need to pass information of interest on to a DAQ system and to block undesired signals may appear to be solved by a simple low-pass, band-pass, or high-pass filter. But it's not that cut n' dry. A better comprehension of these characteristics may be of some help on your next DAQ project! Here are some basic ideas…

Industrial signal-conditioning modules need internal multiple-pole low-pass filtering that has the following characteristics:
(a) specified 3dB frequency (that is: cutoff, corner, knee frequency)
(b) steep attenuation well above the 3dB frequency (20dB per pole per frequency decade)
(c) flat frequency response with minimum ringing or ripples within the pass-band
(d) anti-aliasing function on the field side before amplification.