In my case, I did not needed to smooth the reading of a measurement.
I just needed to improve the cooperation of the DMM with the AC/DC clamp.
My measurements at my tests, was with regulated DC.
About AC, the clamp is so professionally made, that it will handle anything up to 1Khz or even up to 10KHz,
In a hardware level.
The output would still be in mV DC.
Today I did some long lasting tests, I left my large APC 1000XL UPS unit with external battery package,
to totally discharge, and charge.
I have about two hours on battery life, and I did monitored the all process ( took about 4 hours) by monitoring the Amperes of the external battery pack.
Those APC are extremely clever made, when I stopped the Mains,
the UPS become active and started to use exclusively the external battery pack,
and so I measured about 6.5A at 24V as consumption.
Later on, it started to move the load from the external package to the internal one.
And many minutes later, when the internal package started to run out of charge,
the UPS combined the strength of both battery packs.
When both battery packs (27V) fall down to 22V = 11V per cell ( 13.8V), it shut down.
I use to run battery calibration on the UPS once per year,
but this time I had a complete view of what was going on.
I had the Agilent measuring the Amperes with the clamp.
And the Fluke 28II was measuring the voltage.