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the time delay of the system. In this project channel coding and source coding are performed simultaneously which not only boost up the system but also makes data recovery more reliable. Furthermore SNR Vs BER graphs are studied.

DIGITAL Vs ANALOG COMMUNICATION SYSTEMS

The basic difference between digital and analog communication systems depends upon the fact that how their performance is evaluated. Analog communication deals with a set of infinite waveforms so the receiver has to encounter continuous infinite number of waveforms. The performance of analog communication systems can be evaluated on the basis of,Percentage distortion,Expected mean square error,SNR,between the transmitter and the receiver.

On the other hand, in digital communication system, the transmitted signals are represented using finite set of digits and the receiver, in advance, knows about the set. The performance of digital communication systems can be evaluated on the basis of,Probability of error,Probability of incorrect digit detection.

1.2.1 Why to Select Digital Communication?
Our inspiration for selecting the digital communication system lies on the fact that much development has been occurred in this field during the past 50 years. Now-a-days, a major portion of information is carried through digital communication media such as optical fiber, coaxial cable and microwave and satellite channels. Presently, we are bystanding a huge amount of growth in the development of personal communication systems which are based on transmitting the data in digital format such as images, video and voice. We believe that we will be shortly seeing an alternate for analog A.M., F.M. and television broadcast by transmission based on digital communication.

All these developments have encouraged us to follow the increasingly growing trend towards digital communication systems as a medium for transmitting information.

1.3 DIGITAL COMMUNICATION SYSTEM

1.3.1 Basic Elements of a Digital Communication System

Basic elements of a typical digital communication system are,

Input signal
Source encoder
Channel encoder
Modulator
Channel
Demodulator
Channel decoder
Source decoder
Output signal

1.3.2 Block Diagram of a Digital Communication System

1.3.3 Overview of Digital Communication Process

In a typical digital communication system, the first step is to efficiently convert the output of, either an analog or digital source, into a sequence of binary digits by a process called source encoding.

Now, the sequence from the source encoder, in the form of digital digits, is passed to the channel encoder. Channel encoder adds some redundancy in the binary (in the form of 1's and 0's) information sequence. The purpose of adding the redundant data into the binary information sequence is to overcome the effects of noise and interference which corrupts the signal during transmission and with the help of this redundant data, it becomes easier for the receiver to overcome these effects. The addition of redundancy increases the reliability of the received data.

Now, from the channel encoder, the binary data is passed to the digital modulator. The purpose of the digital modulator is to map the bin本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。