Multiplexing: FDM, TDM, WDM Overview

signal to analog signal and the second type is the transformation from the analog signal to the inner signal. And then we have covered the operations of different digital to analog modulation keys such as the amplitude shift key, ASQM, frequency shift key, FSK, phase shift key, PSK, and POP modulation key. Then we need to understand how they refer to the operation.

what is the difference between ASK and FFK and what is the difference between ASK and FFK. And then we have covered the operations of different modulation schemes for analog transmission, such as amplitude modulation, frequency modulation and phase modulation. So most of them AM, FM, PM are used for the radio transmission.

So they don't use the digital data. But they only use the analog transmission from the analog generated original data. So original data was analog. Because their signal is the voice signal. And then this analog signal can be transmitted through the longer distance.

using the modulation from the lower band signal to the higher band signal. By doing so, we can transmit the radio signal to the longer distance. So today, what we will learn is the temperature. First of all, I'm going to talk about how to share the entire bandwidth with

multiple users. So the multiple users will share the single transmission link such as wireless link or wired links. So we're going to learn how we can share the single link with the multiple users. And then secondly I'm going to talk about the several multiplexing schemes such as the frequency division multiplexing Fdn and time division multiplexing TDN and wavelength division multiplexing Wdn.

Okay, so the frequency division multiplexing FDM will divide the frequency among the multiple users. And secondly, the time division multiplexing TDM will divide the time among the multiple users. And wavelength division multiplexing WDM will divide the wavelength among multiple users. And we will talk about these different types of multiplexing schemes. Okay. Okay.

Okay, so first of all, let's define what is the multiplexing. So the multiplexing will be defined as the step of the technique that allows the simultaneous transmission of multiple signals across a single data link. How we can share the single data link with the multi-bludgers? Something like that. So because we use the single data link, the bandwidth will be shared.

So to increase the efficiency of transmission, in the multiplexing, the several information sources will share a large transmission bandwidth. And then there will be another technique such as compression to reduce the number of bits required to represent a given amount of information. And there are concepts that can be understood.

we can combine many individual signals so they can be sent over the one transmission meter. This is the main concept of the multiplexing. Okay, so in order to do the multiplexing, we need the several elements. So the first element is multiplexer in short mux at the transmitter side. And this multiplexer will combine the multiple lines or multiple source.

into a single stream which is many to one. Many sources can be integrated to a single line by the MULT. On the other hand, there exists a D-MULT. We show D-MULT at the receiver side. So this demultiplexer will separate the stream

into each component transmission which is one to many. So the demultiflexer EEMUX demultiflex the single source to the multiple destinations. So the third element of the multiplexing is lifting.

The link is the physical path between the source and destination. And then the left element is channel. The channel is the portion of a link that carries the transmission between a little pair of lines. So this is a single link can be shared by the multiple channels. Let me show you the example of the entire process of the word flexor.

So this is an example of the multiplexing system. There exists mux, dmux, link, and nchannel. Mux, dmux, link, and channel. Nothing like that. So at first, n input lines, n numbers of the input lines can be multiplexed by these mux. to generate a single beam transmission.

And then at the receiver side, this DMOX will distribute the integrated single line into the multiple destinations, which is N output line. So that is the rule of the DMOX and MOX in the multiplexing system. So for example, using a single cable, we can transmit

and independent input to the destination. Suppose that we have multiple lines between me and this student, and this student, and this student, and this student, and all. 10 simultaneous connections between each other. And then using a single link,

which is using the single cable, we can transmit the independent communication between them using the multiplexing and demultiplexing. That's the main concept of the multiplexing here. Okay, then let's take a look at the Bayesian multiplexing techniques. So there are three Bayesian multiplexing techniques, such as the frequency division of multiplexing at the end. Waveright division partiflacing WPM

and time-division multiplexing TDM. So these two multiplexing schemes are analog multiplexing schemes, whereas this TDM multiplexing scheme is digital multiplexing scheme. Okay, so first of all, let's take a look at the FDM first, frequency-division multiplexing. The main idea of this FDM is the similarly operating like divided rate in load.

So if there exists multiple lanes in a road, say there exists 1, 2, 3, 4, 5 lanes. Then each vehicle such as the bus or this vehicle, this vehicle, this vehicle, this vehicle, this vehicle can share a single load using the 5 different lanes.

So this bus will use the first train And these three vehicles use the second train And this truck will use the third train And so on That is the main concept of the frequency division multiplexing FDN Then let's take a look at the operations of FDN So the signal generated by each device

which is 5, will moderate the different carrier frequencies. Then the moderated signals are combined into a single composite signal that can be transported by the region. So this is the example of the frequency system multiplexing when there exists three different input lines to use the three different channels. Channel 1, channel 2, and channel 3. And

Each input will use the corresponding channel to transmit their signal to the destination or receiver. Then the FDN will process infrequency domain perspective. Let's take a look at the three different signals. They are the original signal from the PNC.

frequency of zero to say 4k. This is nothing but the example of the three different signals which are all the signals. Then at first each signal can be moved to the different frequency bands using the modulation. So the first signal will be moved to the

to this frequency band, say F1. And the second signal will be moved to the second frequency band, F2. And the last signal will be moved to the third frequency band, F3. So, okay. And finally, by Mux, F_u_x, these three signals can be integrated into a single link. looks like this

And then finally, the first signal will be allocated to the channel 1, and the second signal will be allocated to channel 2, and the third signal will be allocated to channel 3, and so on. So here, this channel meets the batteries, first-conning batteries, to use F1, F2, and F3, this kind of thing.

Okay, so each source will generate a signal of a similar frequency range. So these similar signals moderate different carry frequencies, F1, F2, and F3, as I said before. And then we can take a look at the comparison between time domain perspective and frequency domain perspective. So this is the title and perspective of the multiplexing.

Okay, so previously, in this figure, this is the frequency domain perspective of the thing. Say, x-axis is frequency, not the time. But if we take a look at the thingar in the time domain, here x-axis will be time. Okay.

So in the perspective of the time domain, each signal, this is the original signal, can be modulated using the corresponding carrier frequency f1, f2, and f3. We already learned about how we can modulate each signal to higher frequency. And then in time domain,

this original signal is transformed to this shape of the signal and the second signal will be transformed into this shape of the signal and the third signal will be transformed into this shape of the signal using the different carrier frequencies F1, F2, and F2 okay? Does it make sense? and then this mux M_x

We integrate the entire signal into a single signal. Then we can see the integrated signal. However, in a time domain signal, we cannot recognize that there is a few periods or not between the signals. Why is that? Because we cannot see the trickles to make sick.

On the other hand, if we draw the same signal in a frequency domain, this original signal will be moved to the corresponding frequency band, F1, F2 and F3, using the modulation scheme. And then by summing these three signals into a single signal, and then we can know that.

there is no interference between each other. There is no overlap signal in a frequency domain. It looks like this. Okay? So that's why we need to transform the original signal in a frequency domain. Or sometimes we need to transform the frequency domain signal to the time domain signal and so on. Okay, then on the other hand, let's take a look at the demultiplexing process.

So this demultiplexing process is a series of filters to decompose the multiplexed signal, the integrated signal, into the corresponding frequency band. And this is the multiplexing process, which is the inverse process of the multiplexing process at the receiver time. So as I showed you in the previous slide, the integrated signal will be decomposed into the corresponding...

using demultiplexor, dmx. And then demodulated signal looks like this. Then finally using the demodulator in pre-conference domain f1, f2, and f3. Then we can regenerate the original signal in time domain. On the other hand, in the frequency domain,

the received signal can be demultiplexed into a series of the signal F1, F2, and F3 by filtering out each signal. Then finally, by using the demodulator, each signal can be regenerated in an original frequency band.

What was your frequent span?

Now let's take a look at the problem about the previous division. So this problem, assume that a voice channel occupies a bandwidth of 4 kHz. One voice channel occupies a bandwidth of 4 kHz. Then we need to combine three voice channels into a link, a single link.

bandwidth of 12 kilometers from 20 to 32 kilometers. Then the problem is that show the configuration using the frequency domain. Assume there are no guard band. Here what is the guard band? This guard band is the frequency band between two neighboring

There exists the signal 1 and signal 2. If we take a look at the two neighboring signals, S1 and S2, there exists a guard band between them to avoid the interpeerance between each other. But here, in this problem, there is no guard band. So that's why...

There is no blank frequency band between the two neighboring signals. S1 and S2. And then what is the entire bandwidth? The entire bandwidth can be... Because we consider the three-fourth channels. S1 and S2 and S3. With the four-year-old channels that we have. Four-year-old channels.

Then the entire bandwidth can be 12 km/h from 20 to 32 km/h That is the considered signal representation in frequency domain Then the generated signal is the frequency domain

voice channel and three voice signals from 0 to 14 and each signal will be modulated using the modulator between the 20 to 24, 24 to 28 and 28 to 32 respectively. And then these signals are integrated using both in transmitter.

to generate this signal from 20 kHz to the 30 kHz. Where the bandwidth is 12 kHz. Then this integrated signal will be transmitted through the beam to the destination receiver. And then, at first, this receiver will emote the integrated signal.

to distribute each signal. This signal, and this signal, and this signal. So here in D-box, D-box will distribute each signal using the pass, then pass pistol, then pass pistol, then pass pistol, and then pass pistol, to generate the corresponding each signal. And then finally, using the b-orderation,

From the higher frequency band to the lower frequency band, we can generate the original signal at the destination receiver. This is the entire process between the transmitter and receiver, which is the multiplexing, demultiplexing, and modulation and demodulation process. However, there is no transformation between digital signal to analog signal.

example shows the entire analog transmission, analog signal transmission from source to destination. There is no conversion between digital signal to analog signal. Why is that? Because the original signal was analog signal, voice signal. And there is no mechanism to transform analog signal to digital signal, or digital signal to analog signal and so on. So actually this example shows the

패스트 텔레폰 서비스 비트윈 더 소스의 데스티네이션 텔레폰 서비스 그냥 전화하는 거죠 전화하는 거는 디지털이 전혀 필요 없고 그냥 목소리를 전달하는 것 같아요 원리까지 전달하는 것 같아요 그 여러 소스들이 하나의 링크를 뭉쳐서 하나의 링크를 통해 가지고 전달해서 각각을 간섭 없이 그냥 전달해주기만 합니다 오케이 그럼 다시 한번 볼게요.

So this problem, five channels, each with 100 kHz bandwidth are to be multiplied together. So each channel has 100 kHz bandwidth. What is the minimum bandwidth of the wind? If there is a need for a broadband of 10 kHz between two neighbor signals on the next tool, we need 10 kHz.

10 kilo hertz of the barf band to avoid interference between them. So because we consider the five channels, S1, S2, S3, S4, S5. And each barf band will be 10 kilo hertz.

and this channel has 100 kHz of bandwidth. Then what is the entire bandwidth, entire minimum bandwidth? It can be calculated by the 10 kHz of the broadband multiplied by 4, 1, 2, 3, 4, plus 100 kHz of the bandwidth and the minimum bandwidth is equal to 5, 1, 2, 3, 4, 5.

the 5.40 kHz of the entire campus.

have an answer to these questions.

Here we need 5 channels with 100 kg. And between two signals, we need an advent of 10 kg. Then the tire, we need 540 kg of tire batteries.

Okay, then let's solve another problem. In this problem, there is four data channels for digital transmission, each transmitting at 1 Mbps, using a satellite channel of 1 MHz, which is a lateral channel. And then, design an appropriate configuration using FDN, frequency division multiplexer. So, here is this problem. We consider four data channels for digital transmission,

and it's transmitting at 1 mega BPS. Right? We consider the 1 mega BPS because of the digital transmission. And this digital transmission will use the satellite channel of 1 megahertz, which is analogous. And then because we need to transmit in total 4 mega BPS of the transmission using 1 megahertz of the LRL channel.

This is our main goal. And then in order to transform the 4Mbps of the digital data to 1MHz of the analog signal. This is our main goal. Our objective. And then in order to make this process between the 4Mbps to 1MHz. Anyway, we need

16 parts to generate the 1MHz of the analog channel. Why is that? Because we need four data channels, four data channels, one, two, three, four. And each data channel has 1MHz, 1MHz, 1MHz, and 1MHz. And then the analog channel can be shared by the four data sources.

That's why each data source should use the 250 kHz of the analog channel. 250, 250, 250. From the 1Mbps to 250 kHz analog signal, we need 60 kHz. Because we need 4 bits per a single symbol to generate from the 1Mbps.

GPS to 250 kHz of the analog bandwidth. From here to here we need 4 bits per symbol. Because we consider 4 bits per symbol, there exists 16 combinations of the data inspiration using 4 bits.

because we can use 2 to the 4 to generate the 16 combinations of the derpage. Say 0000, 000010, something like that. And then the entire combination can be 16. That's why we should use the 16 parts to generate the 250 kms of the analog signal. So that is the final design form.

using the FDM from the digital data to the analog transmission. Different from the previous example which used just analog transmission, the final example we used digital to analog transmission, transformation to transmit the signal over the channel. Because the original data was digital not analog.

So that's why we need this modulation scheme of the digital nanomodulation, such as HAN or FSK, ASK and so on. For another example, if we design 1 Mbps of the digital signal to generate 1 MHz of the nanom signal, We just need an AESK or a PESK.

Something like that. Because this ASK or Fsk will use the single bit to generate the single signal. So that's why. However, this 16 quam is vulnerable to the noise or vulnerable to the error probability compared to the ASK or Fsk. That is the distance advantage of the

16.1 modulation scheme. OK, so then let's move on to the next concept. This is the hierarchical system. So in practice, in practice, the frequency division multiplexing used the hierarchical system to bundle the multiple signal into a single beam. And it's really...

can be also bonded into another link, which is supergroups of the links. And this supergroup also can be bonded into another master group, 정보 and so on and so on. Why is that? Because there exists a lot of links, a lot of connections of the communication in the world. So that's why we need this hierarchical system to bonder the multiple sources to a single link.

그래서 옛날에는 전화 같은 것들이 집집마다 있었는데 그 집집마다 있는 것들 중에서 10개의 집을 묶어가지고 하나의 링크를 만들고 그 여러개의 링크들이 묶여가지고 또 하나의 링크를 만들고 이런 식으로 되는 것입니다. 그래서 그의 링크를 만들고, 그의 링크를 만들고, 48 kHz, 240 kHz, 2.52 mHz, 그리고 그의 링크를 만들고

For the 12 voice channels, 60 voice channels, 600 voice channels, 3,600 voice channels and something

So now let's solve another example in the frequency of the machine. So here the problem is that the advanced mobile phone system, 8 MPS, will use two bands. The first band of 824 to 849 MHz is used for sending. And 869 to 894 MHz is used for receiving.

And then what is the bandwidth between them? 849 minus 824 to obtain 25 MHz of the bandwidth for sending. And 894 minus 886 to obtain 25 MHz of the bandwidth.

each user has a bandwidth of 30 kHz in each direction for sending and receiving How many people can use their cell phone simultaneously? It simply can be calculated by dividing 25

and MHz into 30kHz and then 2500 divided by 30 and you can obtain 2500 divided by 30

and 333.333. Then the answer is 833.333. Then the answer is that how many people can use their cell phone simultaneously. Up to 833 people can use their cell phone simultaneously.

But this test cannot support over the 834 numbers of people, my 10th grade.

Okay, actually this is something kind of a design problem for the cellular system. So compared to the simple calculation problem in the previous case, such a kind of problem is more important in terms of designing the cellular system or designing the communication system as well. So if you understand the frequency of the vertical flexing, ideally,

그리고 이 문제에 대한 제안을 제공할 수 있는 젤료를 제공하는 것입니다. 감사합니다.

Okay, so then let's take a look at another application of the FDM. Actually, this FDM frequency division multiplexing was used in the radio broadcasts such as AM and FM. So, for example, AM is operated between 530 to 1700 kHz. Each station is a...

10kHz of the bandwidth. Okay? 10kHz of the bandwidth. Then for the FM, FM is operated between 88 to 108 MHz. Please compare the units. AM uses the kHz whereas FM uses the MHz. More bandwidth compared to the AM. So in FM, each station is 200kHz of the bandwidth. the 20 times bigger than the AM.

So that's why the voice quality of the FM is much better than the AM. And then for the TV broadcasting. Recently most of TV will be broadcasted by the cable. The cable TV now. But in the past, most of TV will be broadcasted over the air. So that's why they use the frequency of the voice affecting.

to allocate each channel for the 6 megabytes of FDM. And then the other application of FDM can be the first generation of the cellular network. Actually, for the generation of the cellular network, there exist the first generation, second generation, third generation, fourth generation, fifth generation, and third generation. So the first generation of the cellular network is

is analog transmission and from second generation they use the digital transmission and for the third generation they use TDMA, for the fourth generation they use LTE and for the 5C in the fifth generation and for the sixth generation they use the 6G or AI band and so on

So anyway, at the first generation of the cellular network, they use FDN, frequency number, for the ad-on transmission. And for the second generation of the cellular network, they use the digital transmission, which is TDN. Something like that. So in the first generation of the cellular network, each user is assigned to 30 kHz of the chatter.

where the one for sending and the other is for 30. And the voice signal has the 3 kHz of the bandwidth. So it's enough to accommodate the voice signal of the 30 kHz of the chance. So you should be noted that the FM frequency modulation has 10 times of the modulating bandwidth and all the things.

10 times the more than the battery for a carrier is compared to the 3 carriers of the book.

Okay, so until now we have covered the FDM precoce division multiplexion. But from now on let's take a look at the time division multiplexion, TDM. So the main idea of this TDM is that instead of sharing a portion of batteries in FDM, the time is shared with using the full batteries. Let me show you the example of the TDM. So the expression of the TDM is totally different from the FDM.

So in the FDM, they divide each channel in a single link. So a channel, one, channel, two, channel, three, and so on. But on the other end, this TDM will use the entire channel. However, they divide each time.

the press for the user so that's why they are totally different between them one journey I did anything but the remains things are the same with the FDM process so in the TDM they use also must and be but flexor and the FDM flexor to transmit the multiple signal to the destination

So they divide the time, not the frequency. And then let's compare the TDM and FDM. So the TDM is digital multiplexing technique, not the analog multiplexing technique. For combining several low rate channels into one high rate one in terms of frequency. So let me show you the figure of this.

frequency division multiplexing and time difference. So as I said before, the frequency domain frequency division multiplexing will be used entire time but they divide the channel or frequency. So if there exists the 6 source that should be transmitted simultaneously then this channel will be divided into the 6 part.

channel 1, channel 2, channel 3, channel 4, channel 5, channel 6. On the other hand, the time division multiplexing TDM will use the entire frequency band, full frequency band, but they divide the time. Divide the time between each channel. 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, and so on. Does it make sense? However, in order to do the time-dipj multiplexing,

This is very important, synchronous TTI. We need synchronization to do the time division multiplexing between the source and destination. So the data flow of each input data is divided into units. And each input unit occupies one input time slot. So a unit can be one bit, one character, or one block of data. And each input unit becomes one output unit.

And so for example, if the duration of each frame is t, plus t, then the duration of each slot is t divided by n, where n is the number of units. Then the frame is defined as one complete cycle of time slots. So for example, if this system uses the six simultaneous features, and then

the six users will share a single frame with the time. But the time slot, in the time slot, each slot is located to carry data from a specific information. Let me show you this concept in this video. For example, there are three users, user 1, user 2, and user 3. With their corresponding data, A1, A2, and A3. So this data will be divided into its time slot.

and then in the MUX, the multiplexer, the transmitter, they will integrate each data or signal into each frame so in the frame 1, the user data A1, B1, C1 are integrated and for frame 2, A2, B2 and C2 are integrated

And in frame 3, it's B, B, C, B, R integrated. That's all. So that's why each frame is three times large. And its time flat region becomes T divided by 3. OK, now let's talk about the interleaving. What is the interleaving? The interleaving is the process of taking a group of beads from each input line for multiplexing. So a flexed time slot is assigned to an input.

whether it is active or not. So if we look at this figure, so there exists the entire process of the TDM. This is the transmitter and this is the receiver. And transmitter and receiver should share the same synchronization plot. And then at the transmitter,

where exists the original data A, B, C. And in the box multiplexer, they will generate each plane, 1, 2, 3, 4 corresponding units. A1, B1, C1, A2, B2, C2, and A3, B3, C3. And then at the receiver side, because this receiver share the synchronization flap with the TDM,

So that's why this receiver will recognize that at this time the A1 should be generated, or at this time B1 should be generated, at this time C1 should be generated. And then finally the receiver can divide each corresponding data into each part. It's part, it's part, and it's part. Then finally the receiver can regenerate the original data from the transmission.

이 모든 프로세스는 인터리빙 프로세스입니다. 그래서 A1, B1, C1이 섞여서 트랜스 비션되고

데스네이션 에서는 섞인게 다시 풀려 가지고 플라 플라 에 의해서 풀려 가지고 다시 원래 데이터를 구하는 과정 이라서 인터리빙 이라는 표현입니다.

Okay, then this was the TDM multiplexing. And the last one is wave-range division multiplexing, WDM. WDM wave-range division multiplexing is designed to use the high data rate capability of five optic cable. Five optic means the bank cable. And for the operation of the WDM, the multiplexing and demultiplexing in bar signals transmitted through five optic channels.

and the double bands of light from different sources are combined to make a wider band of light. So if we take a look at this figure, there exists three sources with the wavelengths of lambda 1, lambda 2, and lambda 3. And they are integrated into a single beam in the five of tick channel. Then at the destination, they are distributed into the corresponding wavelengths.

Randao, Randao, Randao. So this WDN will combine the multiple light sources into one single light at the multiplexer and do the reverse at the demultiplexer. So actually it looks like the prision like this. The multiplexer and demultiplexer will be implemented using the prision. because it oppresses the light

optical light. So a prision, this prision, bands a beam of light based on the angle of instance and frequency. However, because of its limited application of the medium, it can be only applied to the optical link. So that's why the application of the WDM is not wide. It's too narrow to apply this WDM in the typical medium.

such as the cable or the wire media method.

Okay so this is the end of today's lecture. So let me summarize the today's lecture. Okay so in this lecture we have covered the three different division multiplexing schemes in the analog and digital translation. And the first one is frequency division multiplexing and the second one is high division multiplexing and the third one is frequency and multiplexing. Okay so anyway you need to fully understand the entire process between the multiplexing and

and modulation and demodulation and demultiplexing and so on. Okay? To design your own cellular network system or design your own communication system and so on. Okay? Okay. There is no QR code for today's lecture. So this is the end of today's lecture. Thank you. Any questions? Thank you.

Thank you.

그래서, 어, 전화하기 전에 답답하게 요약을 하자면 음, 어, 손을 이용하는 게 좋은 건 이 3개가 A인이라고 보시면 됩니다. 다시 메일을 해보겠습니다. 그 다음에 멀티플렉싱의 정의를 잘 이해하는 게 중요한 게 있습니다. 소스가 여러 개가 있는데 그것들을 하나로 훔쳐서 하나의 싱글을 A-RT로 두는 게 좋겠습니다. 그리고 반대가 지금의 고객들은, 그리고 이제 M-RT로 운영하는 게 여긴 거고,

트랜스비션의 효율성을 늘리기 위해서 멀티플렉스인 왜냐하면 멀티플렉스가 없으면 우리가 트랜스비션 리클가 10개가 다 필요하니까 근데 멀티플렉스인은 하나의 리클만 가지고 멀티플렉스인은 다 커버를 하시는 거죠 그래서 좋다. 멀티플렉스는 여러 개를 하나로 뭉치는 거죠 이 모의 직렬에 대한 답변을 드리겠습니다.

결국은 핵심은 그거네요. 보시면은 FDM이든 TDM이든 WDM이든 결국 우리가 하나로 합쳤을 때 인터퓨어런스가 생기면 안 되거든요. 간섭이 발생을 하면은 그를 구분을 해낼 수가 없어요. 그래서 핵심은 하나로 합칠 때 구분을 할 수 있도록 해놓고 합친 다음에 나중에 디버티플렉서에서 구분을 해가지고 나누자 라는 게 신 컨셉이에요. FDM이든 TDM이든 WDM이든 이 컨셉은 나중에 우리가 데이터 링크레이어를 배울 때도 비슷한 컨셉으로 많이 나오거든요. 그래서 여러명의 유저들을 하나의 공유된 공간 안에서 어떻게 잘 구분을 할 거 아냐가심이라고 보시면 돼요.

개념들이 여러분 나오니까 알아주시면 좋을 것 같구요 그래서 에프기에는 그 프리퀀 씨를 나누는 게요 근데 시간을 다 쓰는 거죠 아 그런데 어떤 패드를 보면 처음에는 얘가 자리가 안될 수도 있어요 시간을 다 쓰는 어떻게 필거 시를 나오지 이라는 생각을 할 수도 있을 것 같은데 잘 생각해 우리가 타인도매인과 프리퀀시 도매인을 이제 바꿔서 계속 이제 했었잖아요 트랜스포메이션 했었잖아요 했는데 아는 따라 결국은 박 도메인에서 로그 교육이 이렇게 말씀해

어 오듯이 난동안 예를 쓰긴 하는데 얘기하는데 생활 원은 예 왔으면 좋고 채널 2는 예 봤으면 좋고 3쓰는 이마스 그렇게 이해를 하시면 되고 근데 어 파일이 비져 월드 플래스 를 한다는 것은 어 예 예를 하는 거에요 주파수 관점에서는 다 쓰기는 하는데 예를 써놨어 써놨어 써놨어 이렇게 보시면 됩니다 아 그리고 그 요로 포스 에스도 굉장히 중요한 보스죠 그러니까 결국 우리가 뭘 티 플래스 마 하면 되는게 아니라 멀티 플래스 를 할 때 어

어 반성이 발전하도록 해야 되잖아요 그래서 그래서 우리가 모듈레이션 하는게 필요한 거죠 월티레스 하여서요 아 보줄 레이셔 없이 그냥 플레이스 해버린다 이 시그널들 그냥 합쳐 가지고 보내버리면 나중에 일을 구분할 수 없으니까 그러니까 어 월티플레이스 효과 없는 거죠 으 그래서 어 요조 전체 타이어 포세스를 잘 이해하는 게 중요하다

그리고 이것도 이제 타임 도메인 시그늘과 프리퀘시 도메인 시그늘을 나타내는 이렇게 되는데 우리가 이런거 같은 경우에는 지난 시간에 배웠었죠. AM, FF 같은 거. ASK, FSK 같은 걸 배울 때 그리고 캐리어 프리퀘시를 포면 그러면 이렇게 되고 이렇게 되고 하는 걸 배웠잖아요. 그래서 얘들을 그냥 타임 도메인으로 합치면 이렇게 보이지만 얘를 주파크도메인으로 표현하면 노란 모양이 돼가지고 우리가 구분을 할 수 있는 주파수 관점에서 구분을 할 수 있는

다 signal이 된다 라는 거죠. 그러면 나중에 Receiver 안에서 Receiver가 D-Multi-Flacor를 가지고 필터링 아웃하면서 Prequency 영역에서 필터링 아웃을 해서 얘를 D-Modulation 하면 그러면은 오리지날 Prequency Band에 대해서 signal를 얻을 수가 있게 되고 얘를 Time Domain으로 바꾸면 이렇게 내는 거죠. 그렇죠? 그래서 얘는 이제 Time Domain Representation인데

할 도매에서 얻어 미션 대신 너를 바로 필터를 하는 거는 어렵지 팔도 그냥 그래서 예를 제주한 도매인으로 바꾼 다음에 그 다음에 예 그래도 공전의 양면이니까 시그러리 실제로 그 시그사 자체가 바뀌는 게 아니라 해석을 바꾼 거라고 하십니다 회사 그 다음에 프리퀀시 도매인 관점에서 필터 필터는 해당 프리퀀시 대역만 잘라내는 거에요 잘라내서

신호를 생성한 다음에 그 다음에 선생님의 신호를 다시 원래의 드리퍼시 대역으로 가지고 와서 표정적으로 신호를 전달하면 됩니다. 문제들을 풀어보시면 될 것 같고 그냥 이렇게 계산하는 문제들은 당연히 쉬운 문제가 되겠는데 이런 잔플들 있잖아요. 이런 것들은 여러분들이 좀 더 이전에 배웠던 것과 같이 고려해서 그런 문제라서

그리고 디자인적인 요소가 있는 문제들이잖아요. 그런 것들은 시험 문제에 대해 내기도 좋겠죠. 그리고 실제로는 3개, 4개 채널만 쓰는 게 아니라 실제 쓰게 되면 전 세계 정도는 몇 십만 개의 커넥션이 있으니까 그런 것들이 다 하나의 링크로 뭉쳐져서 접속이 되는 게 아니라 계층적으로 12개가 하나로 뭉치고 하나가 또 12개의 형식으로 그런 식으로 해석 계층적으로 시스템이

구성된다. 알려져야겠죠. 또 FDM의 예시는 아날로그 트랜스미션에 대한 예시가 거의 대부분이라고 보죠. FDM도 아날로그 트랜스미션이고 옛날의 TV 옛날 TV는 테이블 TV가 아니라 방송으로 통화했으니까 우선 방송에 아날로그 TV 라고 보시면 될 것 같고 1:1 공신도 아날로그 트랜스미션에 대한 예시가 이렇게 해서

FDM에서 떴다. 그리고 TDM은 Digital Transmission. 채널을 나누는게 아니라 시간을 나눠서 보다. 중요한 점은 Synchronization. 지금에서 보면은 Synchronization이 중요하다. Synchronization이 조금이라도 틀어지면 그러면 A1이 와야 될 자리에 B1이 오고 A1이 와야 될 자리에 C1이 오고 할 수 있잖아요.

그러면 리시버칭에서 완전히 다르게 경험을 하는거니까 되게 중요한 거가 있습니다. 대부분은 이 싱크로라이제이션을 뭘로 쓰냐면 GPS의 진화로 사용합니다. GPS는 굉장히 정확합니다. GPS 시간을 보고 샌드아웃을 집어다이였습니다. 그래서 이것만 봐도 FDM보다 TDM이 훨씬 더 만들기가 어려울 것 같잖아요. 왜냐하면 싱크로라이제이션을 해야 되니까 FDM은 그냥 조금만 나누게 됩니다. 그러니까 FDM은 1세대에 쓰였고 TDM은 2세대에만 쓰이게 됩니다.

주님 아 왜 더블 뒤에 은 뭐 공용적으로 쓰이지 않는데 또 빠요 그 박해 이를 요 체육시장에 많습니다 지금 예 지금의 그들을 나누는 거니까 나무는 방법 자체는 정보 나우 할 일이전이나 뭐 필요 없음 좀 프린거스 일자나 비슷한 것 같아요 왜 그래 슬아 이제 미치니까 미치지 지상 하잖아요 아 딱딱 나눠 쓰이 가요 왜냐 우리가 이제 프리즉만 하고 그냥 빨리 넣어 주파하고 아 아 자는 거 아는 바로 지 너가 아니죠 아는 수도 있지만 예 과이 옵틱 전용 이라서 그렇게 많이 당되지 않습니다

중요한 것은 FDM과 TDM이 훨씬 중요하고 WDM은 이런 5옵티 케이블에 공동을 하시면 됩니다. 공동만 하시면 됩니다. 그렇게 하고 다음 시간에 공동을 통하여 수고하셨습니다.