Understanding APSK and QAM

This video provides an introduction to the basic concepts of amplitude and phase shift keying (APSK) and quadrature amplitude modulation (QAM).
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[@KrampflOtto]

This is one of the best explanations out there! Thank you!

[@pauldenisowski]

Thank you!

[@Nonchalant2023]

Rohde & Schwarz provides better education than my university lol, my classes were like explaining the turbo encabulator now it is so much clearer ++ Thanks

[@yz250ftony]

I work with QAM equipment. Repairing, tuning, and bench testing. Watching the constellation during testing is cool to see live. This technology goes back decades but is still widely used today for cable internet. For sending large amounts of data through copper, this is primary. Fiber is superior, but even that is converted to QAM for coax. ATX, Broadband International, Scientific Atlanta and Arris still manufacture QAM amplifiers. In the beginning, the bandwidth ranged 54-330mhz, then to 450(i think), 550, 750, 860/870, 1,000, and now we're at 1.2hgz. GHZ doesn't play nice with coax over long runs, so eventually to keep up with data rate demands, either the modulation will change, coax will change, or everything goes to fiber. Great presentation!

[@arenaengineering8070]

Simple and straightforward in general terms. Thank.

[@joe_ey2173]

Thank you for the understandable and compact wrap up of the topic! Also the comparison between (A)PSK and QAM really helped me to better understand the topic. Cheers.

[@pauldenisowski]

Glad it was helpful - thanks for the feedback!

[@darktemplari0]

Thanks for the explanations guys, I´ll give it good use. Rohde Schwarz you earned my appreciation.

[@pauldenisowski]

Thanks! Appreciate the feedback!

[@HelmutTschemernjak]

Thanks for this great explanation of the basics, very helpful. Regards from Hannover/Germany, Danke.

[@pauldenisowski]

Thanks!

[@pradeep0037]

Kudos to you on a great presentation. You basically covered the essence of Digital communications subject in my undergrad school. Please keep it coming. Thank you.

[@pauldenisowski]

Thanks for the feedback!

[@balamuralikrishna6082]

This kind of explanation is required for proper understating of the concept . Thanks for such great explanation.

[@pauldenisowski]

Thanks - appreciate the feedback!

[@tingoyeh4903]

You save my day again, thanks.

[@zonglehuang4147]

Thanks a lot. This video has saved me much time.

[@AD_Dongre]

Great ...Love from India🇮🇳

[@CliveReyes]

Very clear and informative. Thanks. Would love to hear more about the Crest factor (PAPR).

[@pauldenisowski]

I actually am planning on a video on this very topic (CF / PAPR) as well as another video on crest factor reduction - stay tuned!

[@CliveReyes]

@@pauldenisowski Fantastic! You earned my subscription.

[@dirkl9652]

Very clear and precise explaination. Thx

[@pauldenisowski]

Thanks for the feedback!

[@sawanbhattacharyya3789]

straight to point thanks

[@harshpreetsingh1228]

Nice presentation

[@kozhenidres314]

it was so informative , thank you alot , what is the name of the playlist than contain this video ?

[@RohdeundSchwarz]

Thank you very much! You can find the playlist here: kzbin.info/aero/PLKxVoO5jUTlvsVtDcqrVn0ybqBVlLj2z8 Test & Measurement Fundamentals. All the best, R&S Social Media Team

[@JonaTheLegend]

Thanks for the video - What does it mean when there are two extra symbols on a 64QAM measurement? I've noticed there are two symbols with 0 and 180 degree phase on every 802.11g measurement I do.

[@pauldenisowski]

Two symbols 180 degrees apart is BPSK (binary phase shift keying). In 802.11g the subcarriers can be modulated with different modulation orders: BPSK, QPSK, 16QAM or 64QAM. So the signal you're looking at has some subcarriers that are modulated with 64QAM and some that are modulated with BPSK. Please see the video "Understanding Phase Shift Keying" for more details on BSPK - thanks!

[@JonaTheLegend]

@@pauldenisowski Thanks for the reply. I looked at the settings on my SPA and it turns out it was called the pilot signal, which I think is the underlying carrier wave.

[@pauldenisowski]

@@JonaTheLegend The pilot signals in 802.11are special subcarriers used to estimate and correct for variations in amplitude and phase caused by the channel and are usually present, so that makes sense. :)

[@RohdeundSchwarz]

👍

[@sirac19]

thx a lot

[@pauldenisowski]

My pleasure - thanks for the feedback!

[@panduwilantara3070]

great

[@pauldenisowski]

Thank you!

[@TheHiphopgems]

I don't understand how you get the number of bits at 2:00

[@user-rf4li7fc7p]

number of bits = log2( modulation order )

[@asdrty258]

Qam or qfm is the thing #ofdm

[@lixiang7349]

Why bother creating the word among when between is used for greater than two anyway.