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प्रश्न
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?
उत्तर
`"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.
संबंधित प्रश्न
Draw a block diagram of a detector for AM signal and show, using necessary processes and the waveforms, how the original message signal is detected from the input AM wave.
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In amplitude modulation, the modulation index m, is kept less than or equal to 1 because ______.
- m > 1, will result in interference between carrier frequency and message frequency, resulting into distortion.
- m > 1 will result in overlapping of both side bands resulting into loss of information.
- m > 1 will result in change in phase between carrier signal and message signal.
- m > 1 indicates amplitude of message signal greater than amplitude of carrier signal resulting into distortion.
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- peak carrier voltage and
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- Is the plot symmetrical about ωc? Comment especially about plot in region ω < ωc.
- Extrapolate and predict the problems one can expect if more waves are to be modulated.
- Suggest solutions to the above problem. In the process can one understand another advantage of modulation in terms of bandwidth?
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