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The antenna current of an AM transmitter 8A when only the carrier is sent but it increases to 8.93A when the carrier is modulated. Find percent modulation. |
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Answer» <P> Solution :The modulated or total power carried by AM WAVE `P_(T)= P_(C)( 1+ (m^(2))/(2))` If R is load resistance , `I_(m)` is the current when carrier is modulated and `I_(c)` the current when unmodulated then,`(P_(T))/(P_(C))= (I_(m)^(2)R)/(I_(C)^(2)R)` `:. I +(m^(2))/(2)= (I_(m)^(2)R)/(I_(C)^(2)R)` Given `I_(m)= 8.93 A, I_(c)= 8A` `:. m^(2)= 2[((8.93)/(8.0))^(2)-1]:. m= 0.7` THEREFORE, PERCENTAGE modulation=70% |
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