# LabVIEW

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## 256 QAM

Hello,

I have downloaded simulated QAM Modulation of an ASCII String and I'd like to know why constellation plot for 256-QAM does not display correctly. Note that I'm totally new to LabView, but we are suppose to analyze and possibly understand how this .vi works for school project

256QAM

Message 1 of 8
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## Re: 256 QAM

What looks wrong to you?  Why? That would be a start of understanding your coursework.

I know what the VI is doing and I see nothing wrong with the output.  We have a difference in understanding.

"Should be" isn't "Is" -Jay
Message 2 of 8
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## Re: 256 QAM

Well maybe I'm not understading it right. I thought that the dots in constellation plot were suppose to look more arranged. Like this:

128QAM

Message 3 of 8
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## Re: 256 QAM

I'd expect each ASCII value to correspond to 1 QAM, thus the spread should mimic the text.

/Y

"Only dead fish swim downstream" - "My life for Kudos!" - "Dumb people repeat old mistakes - smart ones create new ones."
Message 4 of 8
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## Re: 256 QAM

So if I'm understanding it right. One ASCII character is 8 bits and 256QAM can code up to 8 bits into one symbol meaning that if I have text of 256 ASCII characters then it should display all 256 dots?

Message 5 of 8
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Solution
Accepted by topic author Ginrei

## Re: 256 QAM

No, 'A' has ASCII 32, meaning 1 QAM combination, i'm assuming 'AAAA' would repeat the same QAM 4 times.

If you send all ASCII characters you'll have all dots. (given that i'm guessing some on how QAM works)

/Y

"Only dead fish swim downstream" - "My life for Kudos!" - "Dumb people repeat old mistakes - smart ones create new ones."
Message 6 of 8
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## Re: 256 QAM

You are right. I tried to add some other ASCII characters and it started to display more dots. Thank you, sir!

Message 7 of 8
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## RE: 256 QAM

Can you share this example to me? I need this for my project.

Message 8 of 8
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