THE DESIGN, CONSTRUCTION AND TEST ON A TWO STATION SIMPLE INTERCOM SYSTEM. A RESEARCH PROJECT MATERIAL ON PHYSICS
CHAPTER ONE: INTRODUCTION
1.1 INTRODUCTION / BACKGROUND
Human to human communication is an essential part of our everyday activities. Advances in communication technology have enabled any-time-anywhere connection between people. There are a wide variety of devices to communicate with family, friends and workgroup members who are distributed geographically. Cellular phones are used at the working places, stores etc. to call home to be reminded of what is needed or when one will be late to work, meeting etc.
The purpose of a communication system is to transfer information between two or more points. In general, a communications system requires three things namely; a transmitter, a propagation medium, and a receiver. The information to be transferred may be in analog form (example, voice or audio) as in the case of this study where voice is the source of information, or in digital form (computer data, digitalized voice, and so on). The transmitter must have some means of superimposing this information onto its output signal (modulation). The modulated transmitter signal must pass through a propagation medium to a receiver. The propagation medium may be free space, an RF transmission line, or a fiber optic
cable. The function of the receiver is to select (filter) the desired signal, amplify and extract the information. A simplified block diagram of a typical communication system is shown on figure 1. 0 below.
Interest arises in promoting communication within a building which is difficult and stressful going from one point to another within the building in the name of delivering information. In a domestic setting, family members will be collocated within the same building, but often will be unable to be heard using a normal speaking voice. Many households utilize intercom systems to facilitate conversations between remote parts of the home, but these systems have their drawbacks. They require one or both parties to go to specific parts of the house or hold onto a handset in order to communicate. They also offer little ability to direct communication to a person, within the house when the location of the person is initially unknown.