# Reg. AGC3 in gnuradio

**URL:** <https://www.ruby-forum.com/t/reg-agc3-in-gnuradio/236628>\
**Category:** GNU Radio\
**Created:** [September 19, 2013, 11:55pm UTC](https://www.ruby-forum.com/t/reg-agc3-in-gnuradio/236628 "2013-09-19T23:55:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![alcina](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a587f6/32.png) [@alcina](https://www.ruby-forum.com/u/alcina)\
**Post date:** [September 19, 2013, 11:55pm UTC](https://www.ruby-forum.com/t/reg-agc3-in-gnuradio/236628/1 "2013-09-19T23:55:59Z")

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Can someone give me detailed information about the new agc (agc3) in  
gnuradio?.Also is that agc a log mag. loop which is normally used in the  
modern receivers?If there is a block diagram of the new agc3 then it  
would  
also help. Thanks ahead.

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**Author:** ![vamshi\_krishna\_dodl](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/e47774/32.png) [@vamshi\_krishna\_dodl](https://www.ruby-forum.com/u/vamshi_krishna_dodl)\
**Post date:** [September 20, 2013, 9:29am UTC](https://www.ruby-forum.com/t/reg-agc3-in-gnuradio/236628/2 "2013-09-20T09:29:10Z")

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Hi Vamshi,  
a quick look into the GNU Radio Doxygen  
([GNU Radio Manual and C++ API Reference: Level Controllers](http://gnuradio.org/doc/doxygen/group __level__ controllers__blk.html))  
reveals that there is no indication of logarithmics. I guess there is no  
block diagram available, though.  
Also, please refer to the rather well documented source code, the file  
is part of your GNU Radio distribution (and on [gnuradio.org](http://gnuradio.org) and github)  
under gr-analog/lib/agc3\_cc\_impl.cc .  
Since I don’t know how familiar you are with the principles of coding  
blocks: The relevant part is in the work() method.

Greetings,  
Marcus