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Question
A carrier wave of peak voltage 12 V 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%?
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Solution
Amplitude of the carrier wave, Ac = 12 V
Modulation index, m = 75% = 0.75
Amplitude of the modulating wave = Am
Using the relation for modulation index:
`m = A_m/A_c`
`:. A_m = mA_c`
`= 0.75 xx 12 = 9 V`
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