Noise floor of a FM duplex

Question

If these 2 signals, that form this duplex, have ranges of 15-30 [kHz] and 30-45 [kHz] using:

\$NoiseFloor_{dBm} =10\log _{10}(k\times T_{0}\times 1000)+NF+10\log _{10}(BW)\$

and if \$K,T,F\$ and \$\Delta f\$ are given, only thing left to figure out is the \$BW\$ (bandwidth). Is the \$ BW=2(\Delta f+f_{m})\$ where \$f_{m}=2\times 15=30 [kHz]\$ correct formula for the bandwidth of this duplex?

Answer 1

How correct must you be? What you've shown is Carson's rule, where enough of the Bessel function coefficients are included to presumably, in this case, provide quality FM reproduction of music.

Note the lower frequency musical tones are allowed MORE of their Bessel coefficients, thus are more accurately represented. The 15KHz energy is less accurately modeled.