Hi, Sougata ...

You were looking for the cheap way ... a powerful Cy8C29466 ( 32K ) costs here 7 Euros ( 9 US$ ) !!! and the IDE is free ... and no expensive peripheral needed.

That's the reason of my answer.


Q1. How to modulate (AM) the sinewave digitally ?

maybe generating your Analogic output across a full port ( an R-2R ladder ... as simple as this ! ) could solve the problem for a honest 256 steps amplitude resolution ...

Alain