Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

iVARIATION OF BANDWIDTH 71Example: Let the deviation be ± 50 kilocycles and the audio frequencybe 5 kilocycles. Find the bandwidth.The modulation index is 50/5 = 10. From curve A of Figure 5,the increase in bandwidth is approximately 0.42 or 42 per cent, so thebandwidth is approximately 2 (50) (1 + 0.42) = 142 kilocycles.Bandwidth Required for Complex ModulationIf several modulating tones are present simultaneously, the carrierwave can be expressed as[s D 8Ie = E sin < at + ^ — sin (2tt^ + e s ) r (5)I .=i J^swhere E is the amplitude of the wave,