For an amplitude modulated wave, the maximum aplitude is found to be 10 V while the minimum amplitude is found to be 2 V. Determine the modulation index `mu`. What would be the value of `mu` ic the minimum amplitude is zero volt?

Explanation

Let `A_c and A_m` be the amplitude of carrier waves and message signal wave. Given,
`A_(max) = A_c + A_m = 10V`, ………(i)
`A_(min) = A_c - A_m = 2V`………….(ii)
On solving , we get,
`A_c = 6 V, A_m = 4V`
`A_(max) = 6+4 = 10V`.
`A_(min) = 6-4 = 2V.`
Modulation index, `mu = A_m/A_c = 4/6 = 2/3`
When, `A_(min) = 0, then mu = (A_(max) + A_(min))/(A_(max) - A_(min)) = (6+0)/(6-0) = 1`.