Question

In the block diagram of a simple modulator for obtaining an AM signal shown in the figure, identify the boxes A and B.
Write their functions,

Answer 1

In the block diagram of modulator A is Square Law Device and B is Bond pass filter
Band pass filter rejects low and high frequencies and allows a band of frequencies to pass through
Square Law Device is a non linear device. It produces a non linear output of message and carrier signals. The output of square law device

$y\left(t\right)=Bx\left(t\right)+C{x}^2\left(t\right)$
Where B and C are constants and $x\left(t\right)$=message signal $\left(A_{m}sin{\omega }_{m}t\right)$+ carrier signal($A_{c}sin{\omega }_{c}t$).