please tell how to solve this

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vjfaisal

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hi
please help me in this solving this question or kindly tell me the procedure or any formula to easy solve it.


Q:- In AM modulation has the output

y(t)=[A +m(t)]cos(2100t)=[A +Bsin(200t)]*cos(2100t)
the carrier power is 12.5 w, and power efficiency is 27%

claculate values of A,B,and modulation index(m).

best regards
 

please tell how to solve this!!!!!!!!!!!!!

A=Ec=carrier amplitude

B=Em=intelligence amplitude

carrier power = (Ec^2)/2=12.5 --> Ec=A=5


there was a mistake here , see my second post for the rest of the solution
 

Re: please tell how to solve this!!!!!!!!!!!!!

hi ahmed,
is not efficiency= intelligence power/total power
??


 

Re: please tell how to solve this!!!!!!!!!!!!!


yes u r right ..... i am sorry for that mistake

efficiency = intelligence power/total power
=((m^2)/2)/(1+(m^2)/2)=0.27--> m=0.86

m=Em/Ec =B/A --> B=4.3
 

Re: please tell how to solve this!!!!!!!!!!!!!

hi
it is requested to mr ahmes_nasr and amriths04 to kindly give me ur e-mail addresses. if u donot mind it.

and kindly give the idea how to solve above last question.




best regards
 

Re: please tell how to solve this!!!!!!!!!!!!!

hi vjfaisal, you can pm me in here any time.

regards,

vjfaisal said:
hi
it is requested to mr ahmes_nasr and amriths04 to kindly give me ur e-mail addresses. if u donot mind it.

and kindly give the idea how to solve above last question.




best regards
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