# QPSK Constellation

**URL:** <https://www.ruby-forum.com/t/qpsk-constellation/222073>\
**Category:** GNU Radio\
**Created:** [August 10, 2012, 6:19pm UTC](https://www.ruby-forum.com/t/qpsk-constellation/222073 "2012-08-10T18:19:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![aris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/258eb7/32.png) [@aris](https://www.ruby-forum.com/u/aris)\
**Post date:** [August 10, 2012, 6:19pm UTC](https://www.ruby-forum.com/t/qpsk-constellation/222073/1 "2012-08-10T18:19:18Z")

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Hey List,

Is it possible to easily change the QPSK mapping for the PSK  
modulator/demodulators, or does it require a re-compile?

David

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**Author:** ![dgm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/df788c/32.png) [@dgm](https://www.ruby-forum.com/u/dgm)\
**Post date:** [August 10, 2012, 8:08pm UTC](https://www.ruby-forum.com/t/qpsk-constellation/222073/2 "2012-08-10T20:08:05Z")

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There no way to do this simply by passing an appropriate argument but  
you could do it without recompiling by adding in appropriate  
digital.map\_bb blocks into the modulation and demodulation blocks.

On Fri, Aug 10, 2012 at 9:18 AM, David M.

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**Author:** ![dgm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/df788c/32.png) [@dgm](https://www.ruby-forum.com/u/dgm)\
**Post date:** [August 12, 2012, 7:08pm UTC](https://www.ruby-forum.com/t/qpsk-constellation/222073/3 "2012-08-12T19:08:56Z")

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On Fri, Aug 10, 2012 at 2:07 PM, Ben R. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > David

Just to make a note of this, in the 3.7 work that I’ve been doing, one  
of the updates is to add the ability to set the map dynamically for  
the digital.map\_bb block. I hope to be able to roll this into the next  
branch soon.

Tom