Inside Wireless: QAM modulation II

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Inside Wireless: QAM modulation II - The Modulator

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Күн бұрын

QAM modulation is vital to most of modern digital RF radios out there. But what exactly the modulator does? We explain in this episode of Inside Wireless! Learn more: rfelements.com/
Modulation is a process of encoding the digital data - 1 and 0s - onto an RF wave that is more suitable for wireless transmission. The QAM modulator is the circuit inside the radio that takes care of this.
If not sure about the basics of QAM modulation, check our previous video: • Inside Wireless: QAM m...
The basic idea is that the incoming data stream is divided into two branches. The length of the 'symbol', or, the amount of 1s and 0s processed in parallel determines the depth of the modulation. The higher the number, the more data we transfer during one transmission.
The RF carrier signal is brought to both of these branches and multiplied by the amplitude (strength) determined by the input data stream. One branch is called I (in-phase) and the other Q (quadrature). The quadrature means that the I and Q waves are shifted by 90 degrees with respect to each other. After that, the I and Q signals are added to produce the output RF signal.
The increasing data density with growing length of the input symbol is easily seen on an IQ diagram showing each unique symbol the modulator can produce. The higher the data density in the same space, the higher the SNR of the signal needed for successful data transfer - check out this video for detailed explanation: • Inside Wireless: Noise...
Spectral efficiency is a measure of increasing data transfer efficiency with growing QAM depth.
The distances at which the typical WISP radio is capable of working at highest MCS rates are very short - this is again connected to the SNR requirement of the signal and the output amplifier linearity - check our video on this topic: • Inside Wireless: MCS i...
00:00 - Intro
00:42 - QPSK / 4 QAM
01:41 - Constellation diagram
02:26 - 16 QAM - 1024 QAM
03:35 - Spectral Efficiency
04:46 - RF noise challenge
#RFelements #InsideWireless #QAM #QAMmodulation #QuadratureAmplitudeModulation #QAMmodulator #Antennas #AntennaTheory #WISP #SaveSpectrum #RejectNoise #growsmart #UbiquitiNetworks #CambiumNetworks #MimosaNetworks #Mikrotik

Пікірлер: 69

@Rfelements 3 жыл бұрын

How far would you say can QAM go? 2048, 4096... even further? 🤔

@kazievan 3 жыл бұрын

Hi, I like your videos and it is very informative. Are you from Sweden?

@Rfelements 3 жыл бұрын

@@kazievan Thanks, we are from Slovakia :)

@tounsi7orr14 2 ай бұрын

commercial deployment actually : 16384

@algorithminc.8850 15 күн бұрын

Thanks. Good stuff. I look forward to scoping your channel. Subscribed. Cheers

@kyle5555 Ай бұрын

Excellent video. I was a cable guy about a decade ago. Finally finishing up my electrical engineering degree next year. This makes so much more sense now when I was looking at constellation diagrams on my cable meter many years ago. I just knew that sharper meant better lol

@nicolasmasson8569 Жыл бұрын

Thank you so much guys. In 10 minutes with you I understood crucial part of my studies

@hariharanvenkat9761 3 жыл бұрын

Damn bro , this video was excellent man. Ive not seen the concept of IQ explained better anywhere else on the net so far. Thanks a lot you guys!!

@Rfelements 3 жыл бұрын

Thank you! We are happy the videos are useful.

@sabreenaalshooky2407 2 ай бұрын

Very clear explanation, thanks a lot

@asad2880 Ай бұрын

Very useful video, thank you so much

@turrustam Жыл бұрын

This is a good explanation and reference to those who still launching 4G and 5G sites with 30m height. For getting huger MCS and Modulation antennas should be very close to subscribers. I think 15 meter height is more than enough for 5G 3500mhz (sub-6) and without obstacles between antenna and user. Thanks for sharing your knowledge

@rudylopez6546 3 жыл бұрын

That was a great explanation!!! Keep up the great work! I've learned so much from these videos.

@Rfelements 3 жыл бұрын

We are very happy about that! That is the idea of the whole series!

@martinlarsen8626 3 жыл бұрын

Hi there, Your videos are really nice bro., they are short,informative,easy to understand and with very useful and conceptual animations......

@sudanking99 3 жыл бұрын

Great video, making everything so simple and interesting. Keep on and do more great tut .

@Rfelements 3 жыл бұрын

Thank you, we will do our best to keep it up!

@bstanis1237 3 жыл бұрын

Great work and explanation, thanks a lot; best Inside Wireless content in the world.

@Rfelements 3 жыл бұрын

Very flattering, 😊 thank you, we are glad the videos do good for people out there!

@dl569 2 жыл бұрын

very clear, and easy to understand, thanks a lot

@phannguyenvanha5786 2 жыл бұрын

Thanks for this great explanation of the basics, very helpful.I come from in Viet Nam

@Rfelements 2 жыл бұрын

Greetings to Viet Nam, Phan.

@j_g_8391 2 жыл бұрын

Thank you for an excellent video explaining this so clearly. I would only add that I believe SNR is signal power divided by noise power, not minus it, hence why it's called a ratio.

@Rfelements 2 жыл бұрын

You're welcome! Good catch by the way - it is not stated explicitly, but of course we assumed the log scale, so division in linear is subtraction in logarithmic..

@j_g_8391 2 жыл бұрын

@@Rfelements Ah I see! I don't work with RF so didn't realise that log scale typically used, thanks

@vgeorge97 Жыл бұрын

Thank you these videos are great!

@Rfelements Жыл бұрын

Glad you like them!

@hatimbv5896 3 жыл бұрын

My man!!! You should be a teacher :-) Awesome explanation

@Rfelements 3 жыл бұрын

Thanks! 😃

@godfredgyasi1455 3 ай бұрын

After the bit and carrier goes through the product modulator, what do you get? Is the carrier's phase and amplitude changed? If so how does it happen

@usamazahid1 2 жыл бұрын

Amazing illustration..hats off

@andreac6472 3 жыл бұрын

Great Work! Thank you Guys!

@shariulekab Жыл бұрын

Very interesting video

@user-km5xc5co6l 4 ай бұрын

Un transistor npn con be y bc modula por así decir los impulsos acelerados y concomunitantes en la antena 2d

@HICHEMZIMI 5 ай бұрын

amazing explanation ! thank you

@eliasbeik7852 8 ай бұрын

well done

@jccp787 2 жыл бұрын

I am a bit confused about something: It seems that in many diagrams out there, the incoming bitstreams into the mixers are labeled as I and Q, as if this digital data was in quadrature before getting applied to the mixer. However, based on this video, it looks like the data is not actually in quadrature until it mixes with the carriers which is in quadrature, since the 2 sinusoids are 90 degrees appart. So my question is the following: is the incoming bitstream in quadrature already? and if it is, is this a must?

@Rfelements 2 жыл бұрын

The bit stream at the entrance to the modulator is not in quadrature, you got it right, it's the two sin waves that are in quadrature..

@AshwaniKumar-ou4pw 3 жыл бұрын

VERY good video

@CraigMullins1 3 жыл бұрын

Awesome video

@alifrahmatullah4110 3 жыл бұрын

Thanks a lot!

@vlad87999 3 жыл бұрын

Спасибо!

@Rfelements 3 жыл бұрын

now the IW videos have Russian subtitles as well, feel free to share with your friends / colleagues..

@Luxcium 2 жыл бұрын

🤍💙💔

@vgeorge97 Жыл бұрын

Should the position of the 10 and 11 be switched on the QPSK constellation diagram at 2:16?

@Rfelements Жыл бұрын

Hello!. It should not, is the correct way. You start counterclockwise and add +1 in each sector. Results are shown in binary. Thanks

@vgeorge97 Жыл бұрын

Thanks for the reply:) So if the i and q amplitudes are both 1 then does it make a 45 degree angle with the x axis? If so then shouldn't this position correspond to the value 11? Based on the previous animation that showed 1s corresponding to an amplitude of 1 and 0s corresponding to an amplitude of -1.

@shja2008 3 жыл бұрын

how to about RF elements cosider making 11 Ghz antennas ?

@Rfelements 3 жыл бұрын

Maybe in the future, for now we focus on lower frequencies though..

@bhargavreddy8421 3 жыл бұрын

Shrt and crisp👌

@melaro8846 Жыл бұрын

Great video 👍...but, how can QPSK be the same as 4QAM? After all, QPSK has no modulation of the amplitude. There is only one possible level of the amplitude, and the symbols are determined only by the phase shift, unlike for example 16QAM which has three levels of the amplitude (hence the name AM), in addition to the phase shift. Doesn't this mean that 4QAM must have two levels of amplitude, and only two levels of phase?

@Rfelements Жыл бұрын

Hello!. Unfortunately, it doesn't mean that. To have two amplitudes you will need to have them in the constellation diagram (lets say the X axis), and then one of them will be the strongest. In the constellation diagram we show here, which is the one used in 5GHz wireless networks, all the symbols are equally strongest when compared from the center. Also, when you search QPSK and 4QAM you get the same result (neither of them is much used as well). Thanks

@ehsanfaraji6347 Жыл бұрын

just wow

@HICHEMZIMI Жыл бұрын

so usefull thank you

@davidbosshart4448 3 жыл бұрын

So it’s likely not worth paying more for a 1024 qam router vs 256 qam?

@Rfelements 3 жыл бұрын

router is one of the many devices in the chain... it depends if you have customers willing to pay for higher speeds, and if the hardware you use lets you leverage the high QAM rates..

@davidbosshart4448 3 жыл бұрын

@@Rfelements thanks. I ask because I purchased Costco’s Netgear RAXE450 wifi 6e router which has 256 QAM which is different then Netgear’s RAXE500 wifi 6e router that does have 1024 QAM. It was $100 cheaper. I was thinking of returning it to get the full benefits of wifi 6 and future proof with 6 gh band. Thanks

@davidbosshart4448 3 жыл бұрын

Thanks for responding. Correct the bandwidth is a bit lower, however does having only 256 qam still make the raxe450 a wifi 6 router? It is advertised as such but with 256 qam. Thanks again.

@Rfelements 3 жыл бұрын

@@davidbosshart4448 The product spec says it supports 802.11ax, which is marketed as wifi 6.