emulator is a device that mimic the behaviour of a certain chip , it is mainly used for debugging application without having the real chip , it is combined also with some piece of software that gave you the the status of i/o , timers and so on
Simulator is a software program which have software model of the chip. We can debug the codes and plot the out put using Simulator.
But emulator is a combination of hardware and software. Using emulator we got a real time interface.