Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

FREQUENCY MODULATION 49IV.Interference Between CarriersIf two transmitted carriers are received at one time and the beatbetween the two isat audible frequency, the sum of the two producesboth amplitude and phase (or frequency) modulation. If one is twicethe amplitude of the other, the resultant phase modulation amountsto ± 26.5 degrees regardless of the frequency of separation.TO INFINITYCMVILO0F OF AtfxatxtM PTAfSFO0 1/MI7//M C4S£ Of iOFMMM0 MSS CI&CVIT.Fig:. 4This is shown in Figure 5. However, as pointed out in the firstpart of this discussion, the amount of frequency modulation resultingfrom a given amount of phase modulation is a function of the modulatingfrequency, which in this case can be assumed to be the frequencyof separation ,of the two waves. Thus if the two frequencies areseparated by 15,000 cycles, the equivalent frequency deviation of thefrequency modulation amounts to approximately 7000 cycles per second.However, if the frequency of separation is only 100 cycles, the same