# Math library

**URL:** <https://www.ruby-forum.com/t/math-library/239905>\
**Category:** GNU Radio\
**Created:** [March 19, 2014, 10:49am UTC](https://www.ruby-forum.com/t/math-library/239905 "2014-03-19T10:49:54Z")\
**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:** [March 19, 2014, 10:49am UTC](https://www.ruby-forum.com/t/math-library/239905/1 "2014-03-19T10:49:54Z")

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Hi,  
This is the first time I send email to GNURadio Mailing List. Very glad  
to exchange ideas to all members.

Recently, I want to extract RSSI from USRP N210. Is there any system to  
extract RSSI,or I have to build system by myself?

In GRC, is there any library that has math module to calculate square  
and square root

best,  
wishes

owenzhang

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**Author:** ![SS\_SSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/43a26b/32.png) [@SS\_SSSS](https://www.ruby-forum.com/u/SS_SSSS)\
**Post date:** [March 19, 2014, 12:21pm UTC](https://www.ruby-forum.com/t/math-library/239905/2 "2014-03-19T12:21:37Z")

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Hi Owenzhang,

welcome to the mailing list!

GRC is a tool to construct flow graphs of GNU Radio blocks; there is  
no “math library” in GRC, but there are blocks that perform  
mathematical operations. Since you are probably looking for  
sqrt(|x|), try using the “Complex to Mag” Block.

As a side node, since this topic appears about every two months on  
this mailing list: RSSI doesn’t “specify” anything particular. You  
will have to have a model for your signal to explain what a received  
signal strength is – this is something totally different for  
different transmission methods. Therefore, there can never be a single  
system to extract RSSI!

Greetings,  
Marcus

On 19.03.2014 10:14, ?? wrote:

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