Question
For an amplitude modulated wave, the maximum amplitude is found to be 10 V while the minimum amplitude is found to be 2 V. Determine the modulation index, μ.
What would be the value of μ if the minimum amplitude is zero volt?
Solution
The AM wave is given by (Ac + Am sin ωmt) cos ωct where,
Ac is the amplitude of carrier wave and,
Am is the amplitude of message signal wave.
The maximum amplitude is M1 = Ac + Am = 10 V
while,
Minimum amplitude is M2 = Ac - Am = 2 V
Hence, the modulation index is,
When the minimum aplitude is M2 = 0. Then, we have clearly μ = 1, irrespective of M1.
