Question

draw a block diagram of a simple amplitude modulation.explain briefly,how amplitude modulationis achieved.

Answer 1

Let the carrier wave be represented by
c (t)=Asin wt where w = angular frequency of carrier wave
A= amplitude of carrier wave
Let the message or modulating wave be represented by
m (t)=asin wt w=angular frequency of modulating wave
A=amplitude of modulating wave
Therefore x (t)=Asinwt +asinwt
When this is applied to square law device to give output
Y (t)=Bx (t)+Cx2 (t) where B&C are constants





By substituting above x (t) value we get



CAsquare /2 +Casquare /2 which is dc terms


And respective sinusoidal frequency