The PFA-2 distributes amplifier gain both before and after the filter to provide protection from large out-of-band energy or transients that could cause clipping before the filter, distorting the data. Post-filter gain has resolution of better than 0.025% to enable system scaling of the outputs to match the full-scale input of the external recording device. Overload detectors alert the user to over-voltage conditions.

PFA-2 low-pass filters may operate either in a flat mode, for maximally flat pass-band amplitude response with sharp roll-off, or in a pulse mode, for low phase distortion and optimized transient response. Flat mode provides passband characteristics nearly identical to a Butterworth filter while providing a much sharper roll-off. This mode is a good choice for applications such as spectral analysis. Pulse mode has time-domain response similar to the Bessel filter yet provides superior amplitude response characteristics. Pulse mode is ideal for time-domain applications, including transient (shock) measurements and waveform analysis.

The PFA-2 Filter/Amplifier input stage is a balanced differential input topology that may be used to receive differential signals from a bridge type transducer or to condition grounded (single-ended) voltage sources without introducing ground loops. The input is versatile in that it has low DC drift for DC measurement applications, low noise for wideband AC measurements and is equipped with programmable AC/DC coupling. AC coupling is useful for eliminating large DC bias on the signal so that more channel gain can be applied in order to emphasize small AC fluctuations in the signal.