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The antenna current of an AM transmitter is 8A when only the carrier is sent but it increases to 8.93 A when the carrier is modulated .Find percentage modulatio . |
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Answer» Solution :The modulated or total CARRIED by AM wave `P_(T)=P_(C)(2+(m^(3))/(2))` It 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)""therefore l+(m^(2))/(2)=(I_(m)^(2)R)/(I_(C)^(2)R)` Given `I_(m)`=8.93 A, `I_(C)`=8A `therefore m^(2)=2[((8.93)/(8.0))^(2)-1] therefore m=0.7` Therefore ,MODULATION index=70% |
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