MOTM

Can anyone wax eloquent on the origin of the name of the category of 
modules know as Ring Modulators? I've heard a couple of odd theories 
that sound unlikely. It seems simplistic to assume that 
it refers to a particular "ringing" sound that they might be used to 
produce. (I guess I'll really feel dumb if that's what it means!)
Do they always follow an algorithm of X*Y?
~Terry