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Question
Solve the following question.
A message signal of frequency 20 kHz and peak voltage 10 V is used to modulate a carrier of frequency 2 MHz and peak voltage of 15 V. Calculate the modulation index. Why the modulation index is generally kept less than one?
Solution
`"F"_"m" = 20 "kHz" =` Message signal frequency
`"V"_"m" = 10"V"` = Peak voltage do messege signal
`"F"_"c" = 2 "MHz"` = Carrier frequency
`"V"_"c" = 15"V"` = peak voltage of carrier signal
Modulation index = `"V"_"m"/"V"_"c" = 10/15 = 2/3`
To avoid distortion the modulation signal is generally kept less than one.
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