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A sinusoidal carrier voltage of frequency 1200 kHz is amplitude modulated by a sinusoidal voltage of frequnecy 20 kHz. The maximum and minimum modulated carrier amplitudes of 100 V and 90 V are produced. Calculate the frequency of lower and upper side bands, unmodulated carrier amplitude, modulation index and amplitude of each side band. |
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Answer» Here, `v_(c) = 1200 kHz` `v_(m) = 20 kHz` Lower side band frequnecy = `v_(c) - v_(m)` `1200 - 20= 1180 kHz` Upper side band frequency `= v_(c) + v_(m)` `= 1200 + 20 =1220 kHz` Unmodulated carrier amplitude `A_(C) = (A_(max) + A_(min))/2 = 110+90/2 = 100 V` Modulation index `(mu)` `mu = (A_(max)- A_(min))/(A_(max) +A_(min)) = 110-90/110 +90 = 0.1` Amplitude of each side band `= (mu A_(c))/(2) = (0.1 xx 100 / 2) = 5 V` |
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