In amplitude modulation, the modulation index m, is kept less than or equal to 1 because (a) m > 1, will result in interference between the carrier frequency and message frequency, resulting in distortion (b) m > 1 will result in overlapping of both sidebands resulting into loss of information (c) m > 1 will result in a change in phase between the carrier signal and the message signal (d) m > 1 indicates the amplitude of message signal greater than the amplitude of the carrier signal resulting in distortion
Correct options are B) and D) Explanation: Modulation index can be written as, μ=AcAm μ=Vm(max)ΔVmax μ=MaximumfrequencyofmodulatedwaveFrequencydeviation If mf>1 then Δvmax>vm. This means there will be overlapping of both the side bands of modulated wave resulting into loss of information.
