In the previous page we saw different application of signals. But what this Single Concept Learning Module has to focus on is the generic technology behind all these varied applications. They all have one thing in common - they transmit information. The Red signal light informs the driver that he must stop. The Air Traffic Control Tower communicates with many aircrafts which are in its air space. Satellites send and receive information about almost everything, weather forecast, defense, outer space resreach and the list goes on.

Some other forms of signals are X-rays, MRIs, wireless voice and data communication signals.

For understanding a System we can take the example of an X-ray machine. The entire machine constitutes the System that uses the waves/signals of the X-ray to perform the task it is designed for.