FIR OR IIR filter

Hello guys,


I'm measuring AC voltage and AC current. 50-60Hz.


I have 20 samples per 1ms.

Which filter you do recommended for me: FIR or IIR?

The FIR filter will have very high attenuation of specific frequencies when effectively matched. With this relatively high (20 khz) sample frequency relative to the filter objective (50 - 60 hz), the FIR will have good performance when it is tuned to either 50 or 60 hz. The downside will be data storage and computational cost. This will need to be evaluated based on the platform.

You may get sufficiently good performance from various IIR approaches, with much less burden on the system. There are discussions of first order and other filters elsewhere on this forum. Most are (of course) PLC-focused with slower sampling and performance requirements.

I wouldn’t use a FIR or IIR filter. I would integrate and calculate RMS value.