Average identical sweeps or lowpass filter sweeps first? There are 5-10 replicate sweeps of measurements that are meant to be averaged. I also typically lowpass filter the signal at 2000Hz. The target signals are in the 0-100Hz range, and have, for lack of a better term, varying variability (the 5-10 sweeps are usually very similar to each other, but sometimes they are pretty different, but averaging out the variability is fine since it's random).
My question is whether I should (1) lowpass filter the 5-10 sweeps individually before averaging them, or (2) average the 5-10 sweeps and then lowpass filter the resulting mean.
Is there a general rule that applies to this? I am new to signal processing, but I'm aware that order of operations matters.
If your are using a linear time invariant lowpass filter (such as a Finite Impulse Response (FIR) or an Infinite Impulse Response (IIR) filter), and have negligible rounding errors in each operations then doing the lowpass filtering before or after the averaging will yield the same results.
Note that from an implementation perspective, doing the averaging first would likely require fewer computational resources.