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Question
Given modulation index physical significance .For an amplitude modulated wave, the maximum amplitude is found to be 10 V while the minimum amplitude is 2 V. Determine the modulation index μ ?
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Solution
Physical significance of modulation Index.
To determine the strength and quality of transmitted signal. If the modulation index is small, the amount of variation in the carrier amplitude is small. Thus, the audio signal transmitted will not be strong. The greater the degree of modulation, the stronger and clearer will be the audio signal during reception.
Maximum amplitude, Amax = 10 V
Minimum amplitude, Amin = 3 V
Thus modulating index `mu =(A_(max) -A_(min))/(A_(max) +A_(min)) = (10+3)/(10 -3) = 13/7 = 1.85`
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