Quadrature Amplitude Modlation (QAM): Explained

Quadrature Amplitude Modulation (QAM) is used to send large amounts of data by modulating the amplitude of two independent quadrature carrier waves onto a higher frequency carrier wave.
Since these carrier waves are in quadrature they can be coherently demodulated to obtain the independent amplitudes.
QAM allows for extremely large data rates across relatively small bandwiths.

[@TheDjinh]

Best. Explanation. Ever. You must have put so much time into this video. Thank you for that!

[@marioalday5966]

David, this is the greatest explanation on the topic i have found in years (I am 60). BTW your graphics are amazing too.

[@sinan4495]

I feel like one comment isn't enough to express how great this video is. If i could frame this explantation and hang it in my room i would do so in a heartbeat

[@remybouche7483]

As always, a very instructive video with nice animations. Thank you for your work !

[@dmitrytitarenko8281]

Thank you for presenting it in a such straight-forward manner

[@justingilmore1225]

Fantastic! This makes QAM SOOO much easier to understand. Thank you!

[@sinan4495]

I am immensely greatful for this amazing explanation and visualisation of QAM. I have been wrecking my brain for days to understand this topic, but only now i feel like i can finally grasp it

[@shanks6208]

Hahh,Congratulations!

[@brandoneickert]

I'm pretty sure what you refer to as "Amplitude Modulation" in the beginning is actually Amplitude Shift Keying (ASK) in the context of the modulation signal being a digital signal (which it is here).

[@geofish101]

Incredible video, fantastic graphics!

[@dragonfire23141]

Thanks for the incredible video, it finally made QAM click for me.

[@nohaelgammal4782]

I can't thank you enough!

[@3ndr3wmusic56]

I really need to see things visually to understand. This video helped me a lot, thank you very much!

[@asimmohammed6978]

You are Super genius! Best video ever. Thank you! 🙏🙏🙏

[@dominiquelarchey-wendling5829]

Very good explanations of QAM !!

[@jaiisrani2550]

really good visualization of the process!

[@pieterboning]

VERY good explanation!

[@user-mi1dn5gt9x]

David, your video helped me a lot to understand more QAM. What software do you use to make these dynamic graphs? Thank you very much!

[@HICHEMZIMI]

amazing explanation! thank you for the video

[@antoniopellegrini8704]

Fantastic video

[@o2blom]

Very good!

[@Tuk_tuk_22]

❤this is amazing

[@jrthhfdff]

Phenomenal

[@subbox1]

How am I only just finding this channel??

[@Z28videogates]

Another question - what is the minimum difference in power that the RX side would detect as a "different state" for power level? It would seem at more complex states like 1024QAM, if there were 10 different states, the percentage would not be linear like 10%, 20%, ... to 100% but rather in a way that puts it consistent with dBm out (and on the RX side, equal spacing of actual received levels). Would love to hear your thoughts on this. Thanks!

[@ahmadzaklouta]

thank you

[@Z28videogates]

@7:11 Can you please help - I can't find this info anywhere. What differences are they in WiFi in the actual real world? For example, if 1.00 = 10dBm, does .75 = 8.75dBm, .5 (half power) = 7dBm, 0.25 = 4dBm and 0.00 = ? Also, for more complex forms like 1024QAM, would it be 10 difference power level states? Thanks!!

[@chuywillis]

Where can i find this simulator??

[@anlpereira]

Hi, I liked very much this video. In real world, how this could be implemented? I guess it is using op-amps. Is there some real world example you could show us? Thank you very much

[@SabbirImon]

How dose ss7 works and ss7 encryption decryption explain

[@dominiquelarchey-wendling5829]

Could you explain how to get the filtering signal phase sync'd with the carrier signal ? Is frequency sync also an issue, because maybe there could be slight differences in the freq of the emitter and the receiver.

[@PhuLeVan-no5qy]

in 2.15: Why A(1- cos) ~ A

[@ptsmonvideo]

❤

[@jeremy31678]

Should not the top graphs be labelled A_I(t)cos(2pi*ft) & A_Q(t)sin(2pi*ft) beginning from 11:34?

[@mdesm2005]

what's a negative amplitude? (10:00)

[@tumblevveed3586]

🤯

[@marcioaugustotamashiro5940]

Very nice explanation, thanks a lot! Could you share your source code?

[@brandoneickert]

This would be nice!

[@xXThePr0Xx]

In 8:10 you say, we have 2 possible amplitudes but I think this is wrong. The amplitude in a constellation is the distance from the origin to a point. The plot you showed visualizes QPSK/4-QAM, where the amplitudes should always be the same.

[@Manus-hh1hd]

Modulation ka spelling galat hai