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Wave Optics

Question

A carrier wave of peak voltage 12V is used to transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of 75%?

Solution

Peak voltage, A_c = 12 V

Modulation index = 75 % = 0.75

μ = 0.75 = \frac{A_{m}}{A_{c}}

Hence,

A_{m} = 0.75 A_{c}

\Rightarrow

A_{m} = 0.75 \times 12 V = 9 V is the peak voltage .