Hi jyoti raina..
That is a good question you asked.
Well as already mentioned, a fork replicates a signal, and I think it is used for making our simulation tests easier. Suppose you want to check results at two different types of receivers, you don’t need two separate simulations. Instead, you could use a fork.. and give the two signals to two different receivers and analyse results in just one simulation.
On the other hand, a splitter, as the name suggest, divides power /signal into many .
I hope I am clear.
Regards
Naazira.