Section 2 Multiplexing Basics

**9**

**Figure 1.**

*Classification of multiplexing techniques.*

**Chapter 2**

**Abstract**

**1. Introduction**

Multiplexing

*Vijayakumar Nandalal and M.S. Sumalatha*

In any communication system that is either digital or analog, we need a communication channel for transmission. This channel can be a wired or a wireless link. It is not practical to allocate individual channels for each user. Therefore a group of signals are combined together and sent over a common channel. For this we use multiplexers. A multiplexer is a device that allows digital information from several sources to be routed onto a single line for transmission to a single destination. A demultiplexer does the reverse operation of multiplexing. It takes digital informa-

Multiplexing is the process of transmission of information from more than one source into a single signal over a shared medium. We can be able to multiplex analog or digital signal. If analog signals are multiplexed, then this type of multiplexer is called analog multiplexer. If digital signals are multiplexed, then this type of multiplexer is called digital multiplexer. The advantage of multiplexing is that we can transmit a large number of signals to a single medium. This channel can be a physical medium like a coaxial, metallic conductor or a wireless link and will have to handle multiple signals at a time. Thus the cost of transmission can be reduced.

tion from a single line and distributes it to a given number of output lines.

**Keywords:** frequency division multiplexing, time division multiplexing,

code division multiplexing, wave length division multiplexing, orthogonal frequency division multiplexing, amplitude shift keying,

frequency shift keying, phase shift keying
