Model Communication System

Communication systems endeavor to transmit information from

• one to one, i.e. point-to-point communication
• one to many, i.e. broadcast communication
• many to many, i.e. telephone conference call or a chat room

In a typical modern day communication system, the information is in the form of electrical signals (voltage or current), spread over a range of frequencies called the signal bandwidth. 

Some noise gets added to the signal and tries to obscure the desired information.