Nowadays digital communication is became more easy and speedy because of internet and many other things. However, the social media we use and the conference calls all that stuffs are includes in digital communication. Before availability of digital communication, the communication at the long distance was really so Difficult and time consuming.
- What is Digital Communication System?
- Digital Communication System Block Diagram
- What is Encryption?
What is Digital Communication System?
Digital communication system is a system through which we can share different type of data worldwide. Digital communication sends the data via different frequency signal. It has a very important role in our modern society.
Now, we can tweet a thing in second and that is worldwide available to read. However, the beautiful or funny posts you have uploaded on social media and the comments of your friends, that late chats and video calls with your friends and family, this blog that you are reading, that all are possible because of digitalization in communication system.
We are going to see what the science behind this very speedy communication system is. Firstly, we are going to see the technology and main devices requires in it.
Digital Communication System Block Diagram
The diagram starts with the sender, which transmit the data and receiver receives the information at the end. so, the data can be audio, video, image, text or any other type. now, this information maybe analog or maybe digital. If the information signal is in electric signal then it is okay. But, if the information is not in the electrical signal form, (for example audio, video, image or text) then we need to convert them in an electric signal. However, transducer converts the non-electric signal into electric signal. So, after the first block the information is in the form of electrical signal.
The main task of source encoding is to reduce redundancy so we can use bandwidth effectively. However, at this stage the digital data get compromised and there is multiple way to compress the digital data like Huffman coding and Shannon Fano coding. Moreover, for analog redundancy we go for adaptive delta modulation and Pulse-code modulation. So, after this block the signal will be digital.
It is used to provide noise immunity by adding redundancy in it. There are many techniques available for it like Block code, Cyclic code, Convolutional code and many moretechnics are available. After this block the signal will be still digital signal.
Digital Modulator and Antenna
To transmit information at longer distance we need to convert the low frequency digital signal into high frequency analog signal. Digital Modulator multiplies the digital signal we converted in last stage with high frequency carrier signal and convert it in high frequency analog signal so we can easily send it by antenna.There are various technics available for converting signal like Amplitude-shift keying (ASK), frequency-shift keying (FSK), phase-shift keying (PSK) and Quadrature Phase Shift Keying (QPSK). Now, after this block the signal is converted into high frequency modulated signal which antenna will get and transmit further.
Antennas are widely used in the field of digital communication. They receives an electromagnetic wave and convert it into an electric signal or receives an electric signal and convert it into an electromagnetic wave.
Digital Demodulator and Antenna
You may understood by its name that it will demodulate the signal that received by the receiver antenna. And again convert the high frequency analog signal digital signal.
Let’s start from the beginning, We transmitted a signal, firstly that converted into electrical signal(digital or analog). After it we source encoded that signal and converted it into digital signal. Suppose that the source code we get of that is . After doing channel encoding we get signal channel code 011010101(suppose).
Now the digital modulator will transmit the signal but before reaching to the receiver the signal may get disturbed because of noise. So the information may not remain same, it will change. The wrong information will got at the other end. And this thing is dangers. This is why channel decoding is important at the receiver side.
At channel decoding, it will check the received signal is it same as transmitted? For example if it’s 011010100 (transmitted was 011010101). There is one bit error. So, the channel decoder will correct the signal. And if received signal is not changed so channel decoder will do nothing with it.
It will only remove the redundancy so as per our example the code will be  (the front 011 will removed which was added by channel decoder at the transmitter side)
Source decoder will convert the digital signal into the analog signal. And that will again converted into information signal by the speaker, television or any other device.
This is how our one message reach to someone within a second!
Advantages and Disadvantages of the digital communication system
- It is Simple and cheaper because of integrated circuits became smaller, speedy and chep.
- More privacy and security through the use of encryption because, we can re-arrange digital data.
- Data correction, error detection and error correction is possible
- Flexible hardware implementation because, if hardware will change we can change the programing language.
- Easier and sufficient multiplexing by TDMA(Time-division multiple access) & CDMA(Code-Division Multiple Access)
- High power consumption due to multiple stages and complex circuit as we show in the Digital Communication Block Diagram.
- Bandwidth per channel is very high.
- Synchronization is compulsory, if we don’t synchronize the data so there will be many errors in information.
What is Encryption?
Encryption is a method to convert the original information into such type of information that unauthorized third-party can’t understand it.
If you are using WhatsApp messenger you may see something like this written on the top of your new chates.
“Message to this chat and calls are now secured with end-to-end encryption. Tap for more info.”
What does it means?
It means that your chat are safe and no other person can see them. Basically, it is done for increasing privacy and security.There are many different type of encryption methods are available. So let’s understand the encryption with an easy example.
Suppose that you send a message “Hi” to your friends. Its encoded binary code is [ 01001000 01101001 ]
Now, imagine you have created encryption method. Which basically interchange the 2nd and 5th bit of the binary code.
So whenever you will send a message its 2nd and 5th bit of the binary code will exchanged and then send to the other person.
Only you and the other person whom you had sent a message, only you two now that this binary codes’ 2nd and 5th bit is changed. So when the other person will get the message the binary code will get decoded and he or she will get your “Hi” message.
Now if any third person will try to read your message in between the message sending that person will read the binary code as [ 00000000 01101001 ] if that third person will try to decode this message so that third person will get “ i ” which is actually a wrong information(message ).
This is how the messengers and other communication systems use encryption to improve privacy and security.
NOTE : this is not the actual encryption method. Encryption methods are very advanced than this. This was just an example to easily understand what encryption is.
wireless communications globally is something that people can expect as technology advances. Wireless communications has a lot of benefits and can make the world a lot more efficient. It does have concerns though as with every other new advancement that is made in today’s world.
Examples of digital systems that we use every day include mobile phones, television, radio, and of course the Internet. CDs and MP3s are replacing records and tapes, and the number of digital cameras sold this year exceeded the number of analog cameras by a factor of three
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.
Communication Skills: In any digital media role, you’ll need to call upon strong oral and written communications talents to convey information and build relationships with target audiences and clients. Client Relations. Client Services. Collaborating with Creative and Account Teams on Campaigns. Collaboration.
It is an analog radio signal, conveying information digitally. For a close distance transmission like WiFi inside the house between router and a laptop, direct digital communication can be done without using a carrier frequency signal. So in general, the transmission mode for digital signals is analog..
Phones use both analog and digital signals. Mobile phones use analog signals to send and receive a communication signal; however, the information inside that communication signal (text or speech) is actually digital. Similarly, land phones may use analog carriers, but again, all conversations are digital.
Hi, I’m a Blogger & Web-Developer.
Done B.tech from Dharmsinh Desai University, Nadiad