Cheers everyone for all the complementary comments that I receive off you. It makes me happy everytime I know I helped you. As I get various questions regarding all different uses of this, would you be interested in if I started a blog so links that are found could be shared? it could build up a vast array of knowledge to help us all out....?
From Wikipedias PSK article, its stated that "Although the root concepts of QPSK and 4-QAM are different, the resulting modulated radio waves are exactly the same". That is what put me off a bit. Thank you for your quick response and incredibly great videos!
I was confused about difference angle and amplitude. After watching your tutorial , i got clear information . now it is transparent to me . Thanks for the tutorial.
What a shot Robert Webber. I have listen many other people but the way you have explained QPSK is just toooooo awesome. It is simply a crystal clear explanation. Hats off !!!!
Thanks. I just started working in Satellite Communications and was completely clueless to what QAM/QPSK was.... now I have a better understanding. You did a great job
Great Video Robert, I spent 10 years as a fixed wireless access engineer working up to 256 QAM for PtMP radio systems for Cellular back haul. I always had an understanding of this, but your video has made it much clearer.
@@WEBBERSPADE wow, time flies, I just worked it out, it was 2000 - 2009! I've since got into KVM over IP (its different, but many of the principles are relevant). I'll share this with my team as I've often tried to explain it to them.
Hi, Just want to thank you! From Montevideo,Uruguay. The first time I rurally understood qam ,I hope this help me to succeed on my next Modulation course exam.actually studying electrical engineering.
Great! Last time i tried to learn this stuff, it was 3am in a bar in Amsterdam's Red Light District at IBC 2013. Much Easier! :) Great Tutorial thank you!
Mr. Webber I appreciate the response. The QAM topic was actually postponed because the instructor wanted to cover FM/PM first. I can think of two points of feedback that may improve the videos. First would be including a problem and solution to show how the relevant mathematical principals are applied. The second would be using one of those electric pens so the whole thing can play out on a computer screen. It would make viewing easier in terms of glare and having your arm in the way. Thanks!
Wow....amazing tutorial! I've gone through so many websites, documents , books in past few days to properly understand QAM but without any luck. After going through your video I feel much better. You're an amazing teacher. Looking forward to check your all others videos too. Thanks.
Rob, Excellent Video & excellent teaching skills. You may not see yourself good video maker but the way you taught the topic, it was excellent. Thanks for the video.
Mr. Webber, great explanation! I'm an electrical engineer and was looking for a video to explain in simpler terms (i.e. to non-engineers). Your video was quite informative and was exactly what I was looking for, thank you.
I just saw this video.. as some of my friends wanted to know about QAM,QPSK. Have to say amazing effort.. and very good explanation... Sorry to be reviewing this critically.. but at one point you say 0 to 16 for 16 QAM ( its 0 to 15) ... just a very minor error .. but you can probly add as a note or so (it is around 24:11) Finally .. thanks from all of us.. great !
Woooow nice tutorial.I thought that i can't undestand the theory of drawing constelation diagram in my life time.via this tutorial i understood everything about how to draw a constelation diagram...tnx a lot..
Superb explanation, I have been trying to understand these concepts for quite a bit and this is the best way I have come across and finally got to understand very clearly after watching this lecture
OMG... I am studying electrical engineering and you really explain it so clearly.... Amazing work :) Btw, believe it or not: if you ask many electrical students on how they got QPSK, they will not answer it fully like in this video!!!! These kind of basics are very important
Thanks man. As someone who uplinks to satellite every day using QPSK modulated signals, it's nice to understand the science behind it. I get the phase constellation, although I need to find out how you knew that the peaks of the two example waves were '135' and '225' which was then plotted on the polar graph.
Thank you for the video! I am currently taking a Communications Theory class and tomorrow we are covering QAM. I feel much more confident going in now, looking forward to check out the second video now.
To skip all the baby stuff: 9:40. There are different encodings for #QAM (4QAM, 16QAM, etc). Basically, 4QAM encodes different phases (180 degree shifts) of sin and cos to 4 binary numbers such that a cos represents the least significant bit and sin represents the most significant bit. The encoding adds these two waves together, which is then superimposed onto the carrier wave. For instance, for an encoding of 00 (decimal 0, representing +sin and +cos), these two are added (effects amplitude) and is superimposed onto the carrier wave. The encoding used is #QAM (4QAM, 16,QAM, etc), where each number can be represented on a polar graph as a separate vector.
Great piece of work Robert, thanks so much. Do you have any complementary video explaining how X.QAM (X>4) waveforms are built? I mean constellation points with no constant amplitude unlike QPSK has. Thanks!
Hello Stevphie. The 1/2 and 5/6 are referring to a different part to the OFDM System. It is called the code rate. You´ll have to look into that separate from QAM. Basically it is the ratio of what data is repeated. Data gets repeated incase of errors. So in 1/2, half of all the bits received are actually repeats, and in 5/6, only five sixths are useful data when the other sixth is a repetition of data. Search for CODE RATE in OFDM. Let me know how you get on. Take care
Thanks for the video. I came here because I heard that "Modulations techniuqes like QAM and QPSK are used for optical signals". I'm looking to understand how light is used to convey data through fibre optic lines for the internet.
thank you very much for this theory. very well presented! A+!! Only constructive feedback I can offer is for you to not keep replacing the cap on your markers. It became a little bit annoying.
Robert Webber Trust me you're much better than most of my University Lecturers. I have come to find that University Lecturers only have the job because they are pioneers in some aspect of their field and have a "Dr" in front of their name to prove it; not because they know anything about teaching. Every time we encounter a difficult concept I have to watch videos like these. Thank you for the explanation.
men your arm scared me a few seconds XD but dammit, from a student of telecom engineering i must say THANKS MEN, i'm in my last step and your video clear me a lot of things, really thank you
Thank you Robert , enjoyed the tutorial, a subject close to my current interests. Keep up the transfer of knowledge. I have never conceptualized DVB QAM plotted in a linear concept. Spending too much time around PAL vectorscope's skews ones perception . On a side note can you explain what's the purpose of the 4 extra pilot bursts on a 64QAM DVB-T constellation ? I can't understand why such a symmetrical, repetitive, absolute method of modulation needs a fixed amplitude/vectorial reference ? I'm yet to find a complete answer. Cheers
I think u have an error at 23:53. We can get values from 0 to 15 (total 16 different values) but we cant get value == 16 with 4 bits(max 15 -> all ones) But other info is totaly awesome. Thanks for lesson.
Hello Christian, Thanks for the complement! The shift will be relative to the shape of the wave it is currently processing....... Imaging that I´m travelling on my Sine wave, I start at 0, then I curve up to a peak, then I start to fall down, then (and I use this moment as an example) when I arrive at 0 again, instead of carrying on down to a trough I find that my course has changed and I´m now rising up again. That is difficult to explain in words. Another quick video I think I need to make!
GREAT video! I am looking in to different digital modulation schemes to get as much speed as possible and this really explains things in a good way. One thing I struggle to understand though, is what is the phase shift meassured relative to? Is it the phase shift of a sine or a cosine wave?
hey robert, well said man, very very easy to understand.hope it would've been better if u had a director. will you please explain how the signals in OFDM are combined without any interference.
Hey Robert. Have you learned about sin x/x graphs ? It's a key thing in understanding it. Here's a pretty good webpage www.ice.rwth-aachen.de/research/algorithms-projects/ofdm/ofdm-and-the-orthogonality-principle/
Hello Christian, From what all of my teachers, previous colleagues, and test equipment have stated is yes QPSK and 4QAM are the same thing. Maybe some other people may technically define it as something else. But I've never heard that. If you do, please let me know!
I'm glad I could help. How did the class go? Anything you could give me some feedback about? It would be nice to get your views on how this video is helping (that way I can make more to help people further)
Thank you for explaining. I followed this on a mm-paper and I finally see the picture. However: how does it jumps from one to another? Do you pass 'zero'? How does the signal look like if I send e.g. 1 and 2 after one another?
Great tutorial! does the modulation scheme chosen relate directly to bit rate? as there are more combinations (assuming the same symbol rate) or does more symbol combinations relate more to the complexity of the data sent?
world is a better place because there's guys like you !
return the favour Sohan! I'm sure you can contribute to sharing the knowledge too!!
Robert, great contribution to mankind. We will survive as human race because people like you are around.
Oh stop it, I only did it for fun to see what would happen. not for the 100k+ views!!
+Robert Webber okay then please keep doing these things for fun your way to explain things are awesome god bless you ^-^
I agree. Thanks to people like you this society will be better! Thanks for making the complex stuff in a easy thing like this:)
Robert this is ever easiest way to understand constellation diagram at the very basic level,thanks buddy to help me, may God bless you
Cheers everyone for all the complementary comments that I receive off you. It makes me happy everytime I know I helped you. As I get various questions regarding all different uses of this, would you be interested in if I started a blog so links that are found could be shared? it could build up a vast array of knowledge to help us all out....?
yes! great idea!!!!!
cheers mate!
Thank you for this video. I recently got hired by a company that produces cable test equipment and this is helping a lot.
The concept of modulation is finally understood after 5 years of attending university lectures on digital communication...thanks Bob.
From Wikipedias PSK article, its stated that "Although the root concepts of QPSK and 4-QAM are different, the resulting modulated radio waves are exactly the same". That is what put me off a bit.
Thank you for your quick response and incredibly great videos!
I was confused about difference angle and amplitude. After watching your tutorial , i got clear information . now it is transparent to me . Thanks for the tutorial.
One of the only videos out there explaining QPSK from scratch. Awesome video for a first attempt!
What a shot Robert Webber. I have listen many other people but the way you have explained QPSK is just toooooo awesome. It is simply a crystal clear explanation. Hats off !!!!
i did both bachelor and master in communication engineering, and i haven't met someone who explained QAM the way u did ... Thank u so much
Thanks. I just started working in Satellite Communications and was completely clueless to what QAM/QPSK was.... now I have a better understanding. You did a great job
Great Video Robert, I spent 10 years as a fixed wireless access engineer working up to 256 QAM for PtMP radio systems for Cellular back haul. I always had an understanding of this, but your video has made it much clearer.
Glad I could help. Shame you didn't find this earlier as I made it around 10 years ago!!
@@WEBBERSPADE wow, time flies, I just worked it out, it was 2000 - 2009! I've since got into KVM over IP (its different, but many of the principles are relevant). I'll share this with my team as I've often tried to explain it to them.
@@BenedictBrand do you have LinkedIn? I just tried to find you but couldn't. You can find me if you want? "Robert John Webber".
Thank you John. This is the best simple explanation of QAM I have ever come across.
Thanks for taking the time to start at the fundamentals, I think that is the best way to teach and learn.
Thanks a lot for the explanation. I have my exam tomorrow and modulations like this will be part of it. Best greetings from germany.
Hi, Just want to thank you! From Montevideo,Uruguay. The first time I rurally understood qam ,I hope this help me to succeed on my next Modulation course exam.actually studying electrical engineering.
Great! Last time i tried to learn this stuff, it was 3am in a bar in Amsterdam's Red Light District at IBC 2013. Much Easier! :) Great Tutorial thank you!
HAHAHA! I know the feeling. Mine was more at the MWC in Barcelona.
i always hate math and numbers but i love watching people doing it right..great vid bud
Thanks Robert.My lab teacher could not explain me the QPSK graph.And I was really troubled.Thanks again.
Mr. Webber I appreciate the response.
The QAM topic was actually postponed because the instructor wanted to cover FM/PM first. I can think of two points of feedback that may improve the videos. First would be including a problem and solution to show how the relevant mathematical principals are applied. The second would be using one of those electric pens so the whole thing can play out on a computer screen. It would make viewing easier in terms of glare and having your arm in the way.
Thanks!
Wow....amazing tutorial! I've gone through so many websites, documents , books in past few days to properly understand QAM but without any luck. After going through your video I feel much better. You're an amazing teacher. Looking forward to check your all others videos too. Thanks.
Rob,
Excellent Video & excellent teaching skills. You may not see yourself good video maker but the way you taught the topic, it was excellent. Thanks for the video.
All my math classes just came together. Awesome explanation man.
The best explanation of QAM I've ever seen!
Awesome Explanation Robert.... I believe you are the outstanding Professor..Thank a lot and keep posting more video..
Amazing! Your explanations helped me to pass my graduation exam! Thank you! :D
Mr. Webber, great explanation! I'm an electrical engineer and was looking for a video to explain in simpler terms (i.e. to non-engineers). Your video was quite informative and was exactly what I was looking for, thank you.
Wow...Robert. That's super way of explaining. Was dumb about 'QAM'...but no more...Kudos to you.
I just saw this video.. as some of my friends wanted to know about QAM,QPSK. Have to say amazing effort.. and very good explanation...
Sorry to be reviewing this critically.. but at one point you say 0 to 16 for 16 QAM ( its 0 to 15) ... just a very minor error .. but you can probly add as a note or so (it is around 24:11)
Finally .. thanks from all of us.. great !
Woooow nice tutorial.I thought that i can't undestand the theory of drawing constelation diagram in my life time.via this tutorial i understood everything about how to draw a constelation diagram...tnx a lot..
Thank you very much. Your way of explanation is very good. Please keep posting such videos more and more.
Im 16 and that video finally helped me to completely understand it! Many thanks :)
Thanks a lot for such a great video. Just one little thing: in 16 QAM it should go from 0 to 15 and not 16. Thanks again for the helpful video. :)
This is an excellent explanation of QAM for students. Really well explained
Superb explanation, I have been trying to understand these concepts for quite a bit and this is the best way I have come across and finally got to understand very clearly after watching this lecture
Great video! After so much time I can finally understand how these things work! Congratulations and keep up the good work!
Nice tutorial. As Amit, I have finally understood how QAM and QPSK modulation mean.
OMG... I am studying electrical engineering and you really explain it so clearly.... Amazing work :)
Btw, believe it or not: if you ask many electrical students on how they got QPSK, they will not answer it fully like in this video!!!! These kind of basics are very important
hey nice explanation
i loved ur that little board its really aowsome
Thanks man. As someone who uplinks to satellite every day using QPSK modulated signals, it's nice to understand the science behind it. I get the phase constellation, although I need to find out how you knew that the peaks of the two example waves were '135' and '225' which was then plotted on the polar graph.
Hey Robert Thanks for the video , It made it easy for me to Understand the the modulation methods ...You are the Best
I am very proud that I can influence you so positively!
Despite your self declared youth, remarkable explanation.Thanks.
Fantastic!! Clear and concise. Brilliant. Many thanks.
You are the best Robert Webber!! great explanation! Now I will watch part 2 =P ....thanks a lot
Excellent I am major in telecommunication and my final year project is about Qam . Helpful for me thank u . Hope more video
Hello Rob, Thank you for uploading such a simple to follow video on QAM.
Helped me lot in refreshing my basics.
This is such a good lecture I think it is worthy of re-doing with better lighting & sound
Thank you for the video! I am currently taking a Communications Theory class and tomorrow we are covering QAM. I feel much more confident going in now, looking forward to check out the second video now.
Wow, this stuff is easier than I thought. Thanks for the lecture mate!
Great tutorial. Keep doing it for all the concepts in communication... All the very best
To skip all the baby stuff: 9:40.
There are different encodings for #QAM (4QAM, 16QAM, etc). Basically, 4QAM encodes different phases (180 degree shifts) of sin and cos to 4 binary numbers such that a cos represents the least significant bit and sin represents the most significant bit. The encoding adds these two waves together, which is then superimposed onto the carrier wave. For instance, for an encoding of 00 (decimal 0, representing +sin and +cos), these two are added (effects amplitude) and is superimposed onto the carrier wave. The encoding used is #QAM (4QAM, 16,QAM, etc), where each number can be represented on a polar graph as a separate vector.
Hence Check part 2..
thank you very much... this video cleared my concept of QAM.. thnx for your help... ^_^
its really informative and too much vaulable, Can you please share something related to OFDM basics
Great piece of work Robert, thanks so much. Do you have any complementary video explaining how X.QAM (X>4) waveforms are built? I mean constellation points with no constant amplitude unlike QPSK has. Thanks!
Please disregard my comment. I found the 2nd part! Again thx a lot
good presentation sir. its very usefull for my final project presentation....finally wonderfull sir.
thank you RObert. It's really helpful.
Hello Stevphie.
The 1/2 and 5/6 are referring to a different part to the OFDM System.
It is called the code rate. You´ll have to look into that separate from QAM. Basically it is the ratio of what data is repeated. Data gets repeated incase of errors. So in 1/2, half of all the bits received are actually repeats, and in 5/6, only five sixths are useful data when the other sixth is a repetition of data. Search for CODE RATE in OFDM. Let me know how you get on.
Take care
Thank you for explaining, this here is the base of WIFI and satellite TV, to put it simply. NOW I can understand it!
Thanks alot for the very simply and easy to understand explanation, I'm new in all this telecommunication stuff. Hope you do more videos
ROBERT IT'S VERY INFORMATIVE ....U R SUCH A GREAT GENIUS....THANKS A LOT......I REALLY ENJOYED.......
Great!! Finally I understood QAM/QPSK Modulation. Thanks!
Thanks Robert, I was having a really hard time understanding QPSK. This helped a lot!
Thanks for the video. I came here because I heard that "Modulations techniuqes like QAM and QPSK are used for optical signals". I'm looking to understand how light is used to convey data through fibre optic lines for the internet.
Robert this is excellent explanation.
Thanks. It's a real pleasure to have helped you
thank you very much for this theory. very well presented! A+!! Only constructive feedback I can offer is for you to not keep replacing the cap on your markers. It became a little bit annoying.
I am thus a beginner. If I was a professional I would be a university lecturer!
Robert Webber Trust me you're much better than most of my University Lecturers.
I have come to find that University Lecturers only have the job because they are pioneers in some aspect of their field and have a "Dr" in front of their name to prove it; not because they know anything about teaching. Every time we encounter a difficult concept I have to watch videos like these.
Thank you for the explanation.
That was awesome, beautiful breakdown of how to show qam
men your arm scared me a few seconds XD but dammit, from a student of telecom engineering i must say THANKS MEN, i'm in my last step and your video clear me a lot of things, really thank you
excellent. very good explanation and very easy to understand.
Thank you so much for addin this video tutorials onto youtube Robert! I really learned and enjoyed there. Take care!
Great one to learn basics with maths. So how and where it can be used exactly. please make a video on real time application of this.
Good Video. It's been very helpful for the 17 year old son.
Thank you Robert , enjoyed the tutorial, a subject close to my current interests. Keep up the transfer of knowledge.
I have never conceptualized DVB QAM plotted in a linear concept. Spending too much time around PAL vectorscope's skews ones perception .
On a side note can you explain what's the purpose of the 4 extra pilot bursts on a 64QAM DVB-T constellation ? I can't understand why such a symmetrical, repetitive, absolute method of modulation needs a fixed amplitude/vectorial reference ? I'm yet to find a complete answer.
Cheers
WTF know i know the detail about 'polar graph' or constellation diagram. THANKYOU SO MUCH Robert Webber !!!
I think u have an error at 23:53. We can get values from 0 to 15 (total 16 different values) but we cant get value == 16 with 4 bits(max 15 -> all ones)
But other info is totaly awesome. Thanks for lesson.
I got the clear picture now and better understanding on it...thanks a lot bro
Great Job! I hope you do more of these stuff.
Very informative and well presented. Thanks!
Hello Christian,
Thanks for the complement!
The shift will be relative to the shape of the wave it is currently processing.......
Imaging that I´m travelling on my Sine wave, I start at 0, then I curve up to a peak, then I start to fall down, then (and I use this moment as an example) when I arrive at 0 again, instead of carrying on down to a trough I find that my course has changed and I´m now rising up again. That is difficult to explain in words. Another quick video I think I need to make!
GREAT video! I am looking in to different digital modulation schemes to get as much speed as possible and this really explains things in a good way. One thing I struggle to understand though, is what is the phase shift meassured relative to? Is it the phase shift of a sine or a cosine wave?
Thanks Robert. Very good explanation. How much bandwidth is needed for 4096 QAM?
This is a good video to understand QAM thanks robert.
hey robert,
well said man, very very easy to understand.hope it would've been better if u had a director.
will you please explain how the signals in OFDM are combined without any interference.
Hey Robert. Have you learned about sin x/x graphs ? It's a key thing in understanding it. Here's a pretty good webpage www.ice.rwth-aachen.de/research/algorithms-projects/ofdm/ofdm-and-the-orthogonality-principle/
Such a great video! I learnt a lot of new things here! Thank you so much for sharing your knowledge!
Really good explanation... Thanks a lot Robert...
Hello Christian, From what all of my teachers, previous colleagues, and test equipment have stated is yes QPSK and 4QAM are the same thing. Maybe some other people may technically define it as something else. But I've never heard that. If you do, please let me know!
Great explanation ...Keep it up Robert....Thanks
Great video Robert. Very simple. Thanks
Excellent Information shared. Thanks you very much..!!
I'm glad I could help. How did the class go? Anything you could give me some feedback about? It would be nice to get your views on how this video is helping (that way I can make more to help people further)
Thank you for explaining. I followed this on a mm-paper and I finally see the picture.
However: how does it jumps from one to another? Do you pass 'zero'? How does the signal look like if I send e.g. 1 and 2 after one another?
Very good video, easy to understand. Compliments
Thanks Robert, I have managed to work it out myself, these are the points on the axis i.e the phase
Great explanation and a very well done video!
simple and clear..Good job sir..
great effort sir......this lecture clear all my confusion.........thank you.
Great tutorial! does the modulation scheme chosen relate directly to bit rate? as there are more combinations (assuming the same symbol rate) or does more symbol combinations relate more to the complexity of the data sent?
Excellent video, thanks, how did you arrive at the two amplitudes 135 and 225
Robert, clear explanation. Thanks a lot