Does anyone know any sort of a formulas that might give me a clue as to the
relationship between S:N and C:N for an FM system?

I'm playing with narrow FM (500hz deviation kind of stuff), and want to try
to work out the expected S:N for various different deviations with different
C:N radios. Obviously the C:N improves with lower deviation because of the
tighter IF filter, but the S:N will worsen because of the lower deviation,
but I would appreciate some sort of help in the right direction for the
formulas.


Thanks all,

Sam