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A message signal is used to modulated a carrier signal of frequency 5 MHz and peak side-bands are produced seperated by 40 kHz. If the modulation index is 0.75 then the peak voltage and frequency of the messages singal, respectively are |
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Answer» 60 V, 10kHz and peak voltage , ` V_(c) = 40 V ` MODULATION index , ` mu = 0.75 ` ` thereforemu =(V_(m))/(V_(c)) "" [ becauseV_(m)` is peak voltage of message signal] ` 0.75 = (V_(m))/(40) ` ` rArr V_(m) = 40 xx 0.75 ` ` V_(m) = 30 V ` SINCE, difference of frequencies of TWO side bands is equal to the band width (2 fm). i.e., Band width = 40 kHz ` 2f_(m) = 40 kHz rArr f_(m) = 20 kHz ` Hence , the peak voltage and frequencey will be 30 V and 20 kHz . |
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