IIR filters IIR filters are much more efficient than FIR filters, but can introduce linear phase distortions. The IIR filters in BIOPAC hardware are emulated by the software IIR filters.…

Reusable and disposable EDA/GSR electrodes both use isotonic gel but the formulas are different so results will be almost identical but will show a small difference.   The researcher should compare…

Taking a very deep breath and then exhaling, reflexly elicits a general phasic sympathetic discharge, causing a small increase in sweating, which increases electrical conductivity of the skin, thus resulting…

Make sure the unit is turned on and connected to the computer. Check for the green circular icon next to the Start button, which indicates that the unit is connected…

If the Cal 1 and Cal 2 values are very close to zero, check to make sure that: the amplifier is not in AC mode; the filter switches (on the…

All BIOPAC amplifiers have multiple low pass and high pass filter settings. When setting the switches on the amplifier, the following rules apply: The lowest Low Pass filter value will be applied…

A notch filter is typically an aggressive filter that strongly attenuates the power over a narrow region of the spectrum.  For example, a notch filter at 60 Hz / 50 Hz is…

A band pass filter allows the energy concentrated between two given frequencies (X and Y) to pass while it attenuates the signal's energy at other frequencies. It is equivalent to…

High pass filters attenuate the components of a signal below a certain frequency range. They help to remove lower frequency variation — possibly due to signals that are uninteresting in…

Low pass filters attenuate the components of a signal above a certain frequency. They are useful for removing higher frequency variation — for instance, from electrical thermal noise or EMG…

In DC mode, the absolute level of the signal is recorded; no high pass (HP) filters are applied.   DC mode is useful for recording signals such as temperature, force,…

AC mode indicates that a high-pass (HP) filter has been applied to the signal that you are recording. An HP filter removes the low-frequency components of a signal. The most common…