Simulation and modeling - Old Questions

In reality, the system is of neither a pure continuous nor a pure discrete nature. For simulating such system, the combination of analog and digital computers are used. Such setup is known as hybrid computers. The simulation provided by the hybrid computers is known as hybrid simulation.

The form taken by hybrid simulation depends upon the application. One computer may be simulating the system being studied while other is providing a simulation of the environment in to which the system is to operate. It is also possible that the system being simulated is an interconnection of continuous and discrete subsystem, which can best be modeled by an analog and digital computer being linked together.. 

The major difficulty in use of hybrid simulation is that it requires high speed converters to transform signals from analog to digital form and vice versa.