xy wrote:

what's the difference?

i'm looking at specs for the new Emu 1820m.

below are the specs. the common mode rejection always seems to be
many db less than the crosstalk db. i don't think i understand
"common mode rejection".

Common mode rejection is the ability to purposefully combine signals
from two adjacent wires (on a balanced input) to avoid picking up the
noise that they both experience equally along the way.

Crosstalk is when you *accidentally* combine the signals from two
nearby wires (through some kind of coupling) and so each wire's signal
becomes noise on the other wire. Channel separation is the extent
to which you manage to avoid crosstalk.

So basically crosstalk is "hey, you got your peanut butter in my
chocolate" and common mode rejection is "hey, your peanut butter
and my peanut butter were opposite polarities, and they both
got equal amounts of chocolate in them, and now by subtracting
your peanut butter from mine, we have eliminated the unwanted
chocolate."

- Logan