I have been looking at how the delta sigma ADC's have 50/60hz rejection 'built in' in some units. I was wondering how best to do some form of 50/60hz rejection for the AVR's ADC for a single ended input. I have a couple of ADC channels that will be used in a noisy environment with the mains AC close by.
My immediate thought would be a simple 10hz low pass RC, or band reject, but depending on the size of the R and C this could slow down conversion times as one would have to wait for the Cap(s) to charge/discharge to a steady state.
I admit I have no idea on how this could be done in code, if at all.
Just thinking out loud.