Today’s world is heavily
dependent on Digital Communication. Whatever we use for any sort of
communication, it has a niche touch of Digitization. This post will discuss
about various aspects of Digital Communication such as Introduction, Basic
components, How Digital Signal Communication Process works and its various
advantages over Analog Signal Communication.
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Introduction
to Digital Communication
Digital Communication is defined as the process by which Digital devices
communicate information digitally. The communication that occurs in our daily
life is in the form of signals such as sound signals. These sound/ audio
signals are normally analog in nature. For such communication via sound
signals, we must be near the source of sound signal, at least within our
hearing range. But what if the source and receiver are at a long distance? In
case if the communication needs to be established over a distance, the analog
signals are sent through wire, using different techniques for effective and
efficient transmission.
Why
Digitization is needed for Communication?
The traditional methods of communication were using analog signals for
long distance communications. Due to the long distance, the analog signal has
to go through many losses such as distortion, intervention or interference and
even security breach too.
To minimize and overcome these types of losses, the signals are now
digitized using different techniques. With the use of digitized signals, the communication
becomes more clear and accurate with minimum or no losses.
Fig. 2 – Representation
of Digital and Analog Signals
The Fig. 2 above represents analog and digital signals. The digital
signals consist of 1s and 0s which indicate High and Low values respectively.
Basic
Components of a Digital Communication System
Broadly, every digital Communication system consists of these basic
components.
·
Source
·
Input Transducer
·
Analog to Digital Converter
·
Source Encoder
·
Channel Encoder
·
Communication Channel
·
Digital Demodulator
·
Digital to Analog Converter
·
Channel Decoder
·
Source Decoder
·
Output Transducer
·
Output Signal
Fig. 3 – Basic Components of Digital
Communication System
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How
Digital Communication Process Works?
1.
Source
The source consists of an analog signal.
For example: A Sound signal
2.
Input Transducer
This block consists of input transducer which takes a physical input and
converts it to an electrical signal For example: Microphone
3.
Analog to Digital Converter
This electrical signal from Input Transducer is further processed and
converted into Digital Signal by Analog to Digital Converter.
Fig. 4 – Analog to Digital Conversion
4.
Source Encoder
The source encoder compresses the data into lowest number of bits. This
procedure helps in efficient operation of the bandwidth. It removes the
unnecessary bits.
5.
Channel Encoder
The channel encoder, here the coding is done for error correction. During
the transmission of the signal, due to the sound in the channel, the signal may
get distorted. To avoid this, the channel encoder adds some unnecessary bits to
the transmitted data. These bits are the error correcting bits.
6.
Digital Modulator
Here the signal which is to be transmitted is modulated by a carrier. The
carrier is used for effective long distance transmission of data.
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7.
Digital to Analog Converter
The digital signal extracted from the carrier is then converted again into
analog so that the signal can be passed effectively through the channel or
medium.
8.
Channel
The channel provides a path for the signal and permits the analog signal
to transmit from the transmitter end to the receiver end.
9.
Digital Demodulator
This is the place from where the data retrieving process is started at the
receiver end. The received signal is demodulated and again converted from
analog to digital. The signal gets rebuild here.
10.
Channel Decoder
The channel decoder does the error corrections post sequence detection.
The distortions which might take place during the transmission are corrected by
adding some additional bits. Addition of these bits help in the complete
recovery of the original signal.
11.
Source Decoder
The resulting signal is again digitized by sampling and quantizing. This
is done to obtain the unadulterated digital output without any loss of
information. The source decoder creates again the source output.
12.
Output Transducer
This is the final block which converts the signal into its original form
(which was at the input of the transmitter). It converts the electrical signal
into physical output.
For example: Speaker
13.
Output Signal
This is the output for which the whole process is done.
For example: The sound signal received
Fig. 5 – Advantage of
Digital Signal
Advantages
of Digital Communication over Analog Communication
Digital Communication has many advantages over Analog Communication. Some
of them are listed below:
·
The specific signal level of the
digital signal is not very important. Due to this, digital signals are quite
unaffected by the flaws of electronic systems that may spoil analog signals.
·
The configuration process of digital
signals is easier than analog signals.
·
Encryption works better in Digital
Signals (using codes).
·
Digital circuits are more consistent
and reliable.
·
Digital circuits are easy to design
(normally).
·
The cost of manufacturing Digital
Circuits is lesser than Analog Circuits.
·
Digitals Signals do not get corrupted
by noise, interference, and distortions.
·
Cross-talking is very rare in
Digital Communication.
·
Long distance data transmission is
more easy and cheap with Digital Signals.
·
The hardware implementation in
digital circuits is much more flexible if compared to analog circuits.
·
The method of combining digital
signals using Time Division Multiplexing (TDM) is easier than the method of
combining analog signals using Frequency Division Multiplexing (FDM).
·
Digital signals can be saved and
extracted more easily than analog signals.
·
Most of the digital circuits have
almost common encoding techniques and therefore similar devices can be used for
a number of purposes.
·
Digital Communication supports multi-dimensional
transmissions simultaneously.
·
The capability of the channel is
efficiently utilized by digital signals.
·
The signal is unchanged as the pulse
needs a high interruption to change its properties, which is very complex.
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CONTACT US
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Source：electricalfundablog
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