Principles of Communication Systems (PCS)EEE 351Lecture # 08Analog ModulationFrequency Modulation & Comparative Analysis of Analog Modulation Techniques COMSATSSP 2020 (Rev. 1.0)
FM SidebandsCOMSATS PCS •Theoretically, during Frequency Modulation, an infinite number of side bands are formed.•Only few of these sidebands with significant strength are considered for practical purposes.•The sidebands of an FM signal lie symmetrically on both sides of the carrier frequency at equal distances with equal amplitudes.•The spacing between these sidebands is equal to the modulating frequency. B.L. Theraja, S.G. Tarnekar, A.K. Theraja, A Text Book of Electrical Engineering, Volume IV.•A Frequency Modulated signal consists of the following frequenciesfofo±fmfo±2fmfo±3fm•B.W= 2nfmOR B.W=2(1 + mf)fmB.W= 2(Δf + fm)
Modulation Index and Number of FM SidebandsCOMSATS PCS •The number of sidebands depends–Directly on the amplitude of the modulating signal.