Noise and bandwidth in FM/FM radio telemetering

This paper discusses the derivation, limitations, and use of system equations relating input and output signal/noise ratios in fm detection with band-pass and with low-pass output filters and in fm/fm multiplex transmission. The fm/fm equation is: (S/N)
D
= (S/N)
c
(3/4)
^½
(f
DC
/f
S
) (f
DS
/F
UD
) where (S/N)
D
is the output (data voltage) rms signal/noise ratio, (S/N)
C
is the input (radio carrier channel) rms signal/noise ratio, B
C
is the input (radio carrier channel) bandwidth, F
UD
is the output (data voltage) low-pass filter bandwidth, f
DC
is the peak deviation of the carrier due to the subcarrier, f
S
is the center frequency of the frequency-modulated subcarrier, and f
DS
is the peak deviation of the subcarrier due to the data voltage (assumed a sine wave).