Introduction to Analog and Digital Communication | The Basic Block Diagram of Communication System

Summary

This introductory video on analog and digital communication from the ALL ABOUT ELECTRONICS channel explores the basics of information exchange through electronic devices. It covers the types of communication, the role of transducers in converting non-electrical signals, and the function of transmitters and channels in signal transmission. The video also touches on signal characteristics, the importance of signal-to-noise ratio, and the use of repeaters and error correction in maintaining signal integrity over long distances. Viewers are promised further insights into modulation schemes, signal representation, and error correction mechanisms in upcoming videos.

Takeaways

• 😀 The script introduces the concept of analog and digital communication, explaining the basic terminologies and the block diagram of a communication system.
• 🔌 Communication can be either wired or wireless, and it can be point-to-point, point-to-multipoint, or broadcast, like in the case of FM transmission.
• 📡 The script mentions everyday examples of communication systems, such as using a smartphone, sending emails, and watching television.
• 🔍 The block diagram of a communication system includes a source, a transducer, a transmitter with subsystems like modulator, ADC, and encoder, and a channel for signal transmission.
• 🎤 Transducers convert non-electrical signals like voice or images into electrical signals, which are then processed for transmission.
• 📶 The transmitter modifies the input signal for efficient transmission and may include processes like sampling, quantization, and modulation.
• 📈 Modulation alters properties of a periodic signal like amplitude, phase, or frequency according to the input signal, which will be detailed in future videos.
• 📊 Key characteristics of a transmitted signal include whether it's analog or digital, its frequency, bandwidth, data rate, and power level.
• 🌐 The channel, which can be physical or wireless, acts like a filter, attenuating and distorting the signal, and noise is often added during transmission.
• 🔄 The receiver's ability to recover the message signal depends on the signal-to-noise ratio, a critical parameter for the communication system.
• 🔄 Regenerative repeaters and error correction mechanisms are used to extend transmission distance and reduce errors in the received signal.
• 📚 Upcoming videos will cover topics like signal representation using Fourier series and transform, different modulation schemes, digitization and encoding of analog signals, source coding, multiplexing, and error correction mechanisms.

Q & A

What is the basic definition of communication in the context of electronics?

In the context of electronics, communication is the exchange of information between two points using electronic gadgets and devices, which can be either wired or wireless.

What are the different types of communication systems mentioned in the script?

The script mentions point-to-point communication, point-to-multi-point communication, network communication, and broadcast communication, such as FM transmission.

What is the role of a transducer in a communication system?

A transducer converts non-electrical forms of information, like voice or images, into electrical signals. Examples include microphones, CCD cameras, and computer keyboards.

What happens to the input signal after it passes through the transducer?

After passing through the transducer, the input signal is modified by the transmitter for efficient transmission. This may involve processes like modulation, analog-to-digital conversion, and encoding.

What is modulation in the context of communication systems?

Modulation is the process of altering the properties of a periodic signal, such as amplitude, phase, or frequency, according to the input signal to prepare it for efficient transmission.

What are the characteristics of a transmitted signal that are important to consider?

Important characteristics of a transmitted signal include whether it is analog or digital, its frequency, the range of frequencies (bandwidth), the data rate or bit-rate for digital signals, and the power level.

What is a channel in a communication system and how does it affect the transmitted signal?

A channel is the medium over which the signal is transmitted, such as optical fiber, coaxial cable, or radio link. It can behave like a filter, attenuating different frequencies of the transmitted signal differently and introducing noise.

Why is the signal-to-noise ratio important in a communication system?

The signal-to-noise ratio is crucial as it determines the clarity of the received signal. A higher ratio improves the ability of the receiver to recover the message signal from the distorted signal.

What are regenerative repeaters and how do they help in communication systems?

Regenerative repeaters are devices used to extend the transmission distance. They detect the distorted and noisy signal, regenerate a fresh copy of the transmitted signal, and retransmit it over the channel.

What are the key specifications to consider for a transmitting medium or channel?

Key specifications include the length of the channel, the bandwidth supported by the channel, and the maximum supported data rate for digital signals.

What happens to the received signal at the receiver in a communication system?

At the receiver, the received signal is demodulated. For digital signals, it is first decoded and then converted back into an analog signal using a digital-to-analog converter, before being amplified and sent to the output transducer like a speaker or display screen.

Outlines

00:00

📡 Introduction to Analog and Digital Communication Systems

This paragraph introduces the concept of communication in electronics, explaining it as the exchange of information between two points using electronic devices. It covers the basics of communication, including the different types such as wired, wireless, point-to-point, multipoint, and broadcast systems. The paragraph also introduces the basic block diagram of a communication system, starting with the source of the message signal, which can be converted into an electrical signal using a transducer. The transmitter's role in modifying the input signal for efficient transmission is discussed, including the subsystems involved like modulators, analog to digital converters, and encoders. The importance of understanding the transmitted signal's characteristics, such as whether it's analog or digital, its frequency, bandwidth, data rate, and power level, is emphasized for effective communication link design.

05:02

🔌 Signal Transmission and Reception Challenges

This paragraph delves into the challenges faced during signal transmission and reception. It describes how the transmitted signal gets attenuated and distorted as it passes through the channel, with noise superimposed over it. The importance of the signal-to-noise ratio for the receiver's ability to recover the message signal is highlighted. The paragraph also discusses methods to overcome signal degradation, such as using regenerative repeaters to refresh the signal and error correction mechanisms to reduce errors in digital signals. Furthermore, it outlines important channel specifications like length, bandwidth, and data rate, and explains the process at the receiver end, which includes decoding, converting the signal back to analog, and amplifying it before it's output through a transducer like a speaker or display. The paragraph concludes with a preview of upcoming topics in the video series, such as signal representation using Fourier series and transform, modulation schemes, digitization and encoding of analog signals, source coding, multiplexing, and error correction mechanisms.

Keywords

💡Communication

Communication is the central theme of the video, referring to the exchange of information between two or more points. In the context of the video, it specifically addresses electronic communication, which uses electronic gadgets and devices to exchange information over distances. Examples from the script include talking on a smartphone, sending emails, and watching television, all of which are forms of communication systems.

💡Analog Communication

Analog communication is a method of transmitting information using continuous signals that can vary over time. The video introduces this concept as one of the two main types of communication, contrasting it with digital communication. An example of analog communication mentioned in the script is FM transmission, where information is broadcasted at a particular frequency.

💡Digital Communication

Digital communication involves the transmission of information in the form of discrete digital signals, typically using binary digits (bits). The script discusses digital communication as an alternative to analog, highlighting its use in modern communication systems such as email and digital television.

💡Transducer

A transducer is a device that converts non-electrical energy into electrical energy, which is crucial for electronic communication. In the video, transducers like microphones and CCD cameras are mentioned as examples that convert voice and visual information into electrical signals, respectively, for transmission.

💡Transmitter

The transmitter is the component of a communication system that prepares the input signal for efficient transmission. The script describes how a transmitter can modify the input signal through various subsystems such as modulators, analog-to-digital converters, and encoders, which are essential for the process of communication.

💡Modulation

Modulation is the process of altering a periodic signal, such as amplitude, phase, or frequency, in accordance with the input signal. The script explains that modulation is used for efficient transmission and that it will be discussed in more detail in upcoming videos, indicating its importance in the context of communication systems.

💡Signal-to-Noise Ratio (SNR)

Signal-to-Noise Ratio is a measure of the level of a desired signal compared to the level of background noise. It is a critical parameter in communication systems, as mentioned in the script, because it affects the ability of the receiver to recover the original message from a distorted signal.

💡Repeater

A repeater is a device used to extend the range of a signal in a communication system. The script describes regenerative repeaters, which detect a distorted and noisy signal and regenerate a fresh copy of the transmitted signal for further transmission, thus increasing the transmission distance.

💡Error Correction

Error correction is a technique used in digital communication to reduce errors in the received signal. The script mentions the use of error correction mechanisms and redundancy in the message signal to improve the reliability of digital communication.

💡Channel

In the context of the video, a channel refers to the medium over which the signal is transmitted, such as optical fiber, coaxial cable, or radio links. The script discusses the importance of channel characteristics like length, bandwidth, and supported data rate in determining the quality of communication.

💡Bandwidth

Bandwidth is the range of frequencies that a channel can transmit with reasonable fidelity. The script uses the term to describe an important specification of a channel, which determines the capacity for data transmission, such as a channel that supports frequencies up to 20 kilohertz having a bandwidth of 20 kilohertz.

💡Data Rate

Data rate, also known as bit rate, is the amount of digital data that is transmitted per unit time. The script mentions data rate as a critical aspect for digital signals, indicating the maximum supported data rate by a channel, which is essential for understanding the capacity of the communication system.

Highlights

Introduction to analog and digital communication.

Communication is the exchange of information between two points.

Information exchange can be wired or wireless.

Communication can be point-to-point, point-to-multipoint, or broadcast.

FM transmission is an example of broadcast communication.

Daily use of gadgets involves sending and receiving information.

Basic block diagram of a communication system explained.

Transducer converts non-electric signals into electrical signals.

Transmitter modifies the input signal for efficient transmission.

Transmitter includes modulator, analog to digital converter, and encoder.

Signal is sampled, quantized, and converted into digital form.

Modulation alters the properties of a periodic signal according to the input signal.

Characteristics of the transmitted signal include type, frequency, bandwidth, and power level.

Channel acts as a medium for signal transmission and can be physical or wireless.

Signal attenuation and distortion depend on the length of the channel.

Signal-to-noise ratio is crucial for signal recovery.

Regenerative repeaters are used to extend transmission distance.

Error correction mechanisms reduce errors in digital signals.

Channel specifications include length, bandwidth, and supported data rate.

Receiver decodes and converts the signal back to analog form.

Upcoming videos will cover Fourier series, Fourier transform, modulation schemes, digitization, encoding, source coding, multiplexing, and error correction.

Transcripts

Hey friends welcome to the YouTube channel ALL  ABOUT ELECTRONICS. So this is the introductory  

video on the analog and the digital communication.  And we will see some basic terminologies,  

and the basic block diagram of the communication  system. So in a very basic sense the communication  

is the exchange of information between the  two points. And in electronics point of view  

using the electronic gadgets and the devices  the information can be exchanged between the  

two points, which are far away from each other.  So this exchange of information could be wired  

or the wireless. And the communication could  be point-to-point communication, or point to  

multi-point, or even it could be in the network  also. And many times this communication could  

be even the broadcast also. Where from one  station the information is broadcasted. And  

one such example is the FM transmission. Where  a reduced station broadcasts the information at  

a particular frequency, and anyone can tune  the receiver to the particular frequency,  

or the channel to receive the information. And  in fact using the gadgets we are sending and  

receiving the information every day. Like talking  on a smart phone, or sending an email to someone,  

and even watching the television are the examples  of the different communication system. So through  

a basic block diagram of the communication system,  let us understand how the information is extent  

between the two points. So in this block diagram,  the first block is the source itself, from where  

the message signal is generated. So this message  could be voice, email, or the television signal,  

or it could be even some data signal. So if  this message is in non-electric form, then  

using the transducer, it is converted into the  electrical signal. So the microphone, CCD camera,  

and the computer keyboard are the examples of the  transducer. For example using the microphone our  

voice can be converted into the electrical signal.  And using the camera the picture or the motion can  

be converted into the digital signal. So after  this transducer the electrical signal, which we  

have is known as the input signal. Then after this  transducer, the next block is the transmitter. So  

this transmitter modifies the input signal for  the efficient transmission. And this transmitter  

module also contains several subsystems. Like  the modulator, the analog to digital converter,  

and the encoder. And many times it also contains  the amplifier system. For example if the signal  

is analog in nature, and it needs to be converted  into the digital form, then first it is sample at  

the regular intervals. And then it is quantized  and after the quantization using the analog  

to digital converter, it is converted into the  digital form. And later it can be encoded in a  

particular format using the encoder. And usually  for the efficient transmission the signal is  

modulated using the particular scheme. So this  modulation is the process, where the property  

of the periodic signal like the amplitude, phase,  or the frequency is altered according to the input  

signal. And of course in the upcoming videos  we will talk in detail about this modulation.  

So anyway these are the some of the subsystems  of this transmitter module. Now when we talk  

about the transmitted signal, then we need to  know certain characteristic of this transmitted  

signal. Like whether it is analog, or the digital  signal. What is the frequency of the signal? If it  

contains multiple frequencies, then what is  the range of frequencies in the transmitted  

signal. Or in other way what is the bandwidth  of the transmitted signal. And if the signal  

is transmitted in the digital form, then at which  rate the data is transmitted. Or in other words,  

what is the data rate or the bit-rate of the  transmitted signal. Then another important aspect  

is the power level of the signal. Because that  will decide how long the signal can be transmitted  

over a particular medium faithfully. So these are  the some of the aspects which are very important  

for the transmitted signal. And one needs to see  these aspects while designing the communication  

link. So the signal after this transmitter is  known as the transmitted signal. And this signal  

is sent over the particular channel. So a channel  is the medium over which the signal is transmitted  

over the certain distance. So this channel  could be a physical channel, like optical fiber  

or the coaxial cable. Or it could be a wireless  channel like a radio link. So this channel partly  

behaves like a filter and attenuates the different  frequencies of the transmitted signal differently.  

So once the transmitted signal passes through  the channel and gets received at the receiver,  

then it gets attenuated as well as the distorted.  Moreover the noise also gets superimposed over the  

transmitted signal. So if this is the transmitted  signal at the transmitter end, and at the receiver  

we may receive the attenuated as well as the  distorted signal. And by what amount the signal  

will get attenuated and the distorted, will depend  on the length of the channel. So if the signal  

travels longer in a particular medium, then the  attenuation and the distortion of the signal will  

be more. But the detector or the receiver should  be able to recover the message signal from this  

distorted signal. And whether the detector is able  to recover the signal or not, it depends on the  

signal-to-noise ratio. So it is a very important  parameter in the communication system. So this  

parameter is the ratio of the signal power to the  noise power. So by increasing the signal power,  

the signal-to-noise ratio can be improved, and the  signal can be transmitted over a longer distance  

faithfully. Now many times the signal needs to be  transmitted over much longer distance. And it is  

not possible to increase the signal power beyond  the certain limit. So in such case a regenerative  

repeaters are used after the certain distance. So  these regenerative repeaters detects the distorted  

and the noisy signal, and generates the fresh  copy of the transmitted signal. And that signal  

is once again transmitted over the particulars  channel. So this is another way to increase the  

distance over which the signal can be transmitted.  Apart from that, for the digital signals using the  

error correction mechanism and by adding the  redundancy in the message signal the error in  

the received signal can be reduced. So for a  transmitting medium, or a channel perspective  

following are the important specifications.  The first is what is the length of the channel,  

or a distance over which the signal can be  transmitted faithfully. Then another important  

specification is the bandwidth of the channel.  So it is the range of the frequencies which is  

supported by the channel with reasonable fidelity.  For example if a particular channel can transmit  

the signal in the range of 0 to 20 kilohertz, then  we can say that the bandwidth of the channel is 20  

kilo Hertz. And if the signal is transmitted in  the digital form, then for the digital signal  

the another important aspect is the data rate.  That is the maximum supported data rate by the  

particular channel. So these are the some of the  important aspect for the channel perspective.  

Now at the receiver, these received signal is be  modulated. And if the signal is in digital form,  

then first of all it is decoded and then using  the digital to analog converter, it is converted  

into the analog signal. And after the proper  amplification, this signal is given to the output  

transducer. So this output transducer, could be  a speaker, or it could be even a display screen  

of the smartphone or the monitor. So this is the  basic block diagram of the communication system.  

And a little overview of how the information or  the message is transmitted from one point to the  

another point. So in the upcoming videos, we will  see how to represent the signal using the Fourier  

series in the Fourier transform. And then we  will also talk about the different modulation  

schemes. And in the digital communication  we will also see how the analog signal can  

be digitized and encoded. So we will discuss about  the source coding. Then we will discuss about some  

multiplexing schemes. And we'll also see different  error correction mechanisms, which is used in the  

communication. So these are the some of the topics  we will discuss in the upcoming videos. But I hope  

in this video, you got the basic overview of  the analog and the digital communication. So  

if you have any question or suggestion, do let  me know here in the comment section below. If  

you like this video, hit the like button and  subscribe the channel for more such videos.