# QAM and Chunks\_to\_Symbol

**URL:** <https://www.ruby-forum.com/t/qam-and-chunks-to-symbol/242592>\
**Category:** GNU Radio\
**Created:** [July 6, 2015, 7:41am UTC](https://www.ruby-forum.com/t/qam-and-chunks-to-symbol/242592 "2015-07-06T07:41:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [July 6, 2015, 7:41am UTC](https://www.ruby-forum.com/t/qam-and-chunks-to-symbol/242592/1 "2015-07-06T07:41:15Z")

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Hello,  
How can I specify symbol table and dimension for QAM in  
chunks\_to\_symbol  
block? which modulation is indicating in fsm\_utils.py by orth2 orth4?  
Can anybody help me. I am new to this GnuRadio.  
ThankYou

With Regards,  
Salija.P

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<div class="post-metadata">

**Author:** ![Salija\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Salija\_P](https://www.ruby-forum.com/u/Salija_P)\
**Post date:** [July 6, 2015, 8:30am UTC](https://www.ruby-forum.com/t/qam-and-chunks-to-symbol/242592/2 "2015-07-06T08:30:54Z")

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For small constellations, you can just specify the points manually.  
Here’s an example for 16QAM. Just paste into the “Symbol Table” field in  
the block properties. The dimension is 1.

[complex(3,3), complex(3,1), complex(1,3), complex(1,1), complex(3,-3),  
complex(3,-1), complex(1,-3), complex(1,-1), complex(-3,3),  
complex(-3,1), complex(-1,3), complex(-1,1), complex(-3,-3),  
complex(-3,-1), complex(-1,-3), complex(-1,-1)]

Ron