Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

14 FREQUENCY MODULATION, Volume IDividing (16) by (14) to obtain the ratio between the frequency andamplitude modulation output signal-noise ratios givesSf/N f rF d(peak values, impulse) =2 —(17)Equation (17) shows that the frequency modulation peak voltageimprovement with respect to impulse noise is equal to twice the deviationratio or about 1.16 times more improvement than is produced onfluctuation noise. The peak power gain would be equal to the squareof the peak voltage gain or four times the square of the deviation ratio.Low Carrier-Noise RatiosWhen the expression for the instantaneous frequency of the wavemodulated by the noise component and signal, given by (7), is resolvedinto its components by the use of the binomial theorem, the followingis the result:/F c — F d sin pt —(18)