# Measure the peak of FFT and its frequency

**URL:** <https://www.ruby-forum.com/t/measure-the-peak-of-fft-and-its-frequency/241647>\
**Category:** GNU Radio\
**Created:** [April 21, 2015, 5:50am UTC](https://www.ruby-forum.com/t/measure-the-peak-of-fft-and-its-frequency/241647 "2015-04-21T05:50:13Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [April 21, 2015, 5:50am UTC](https://www.ruby-forum.com/t/measure-the-peak-of-fft-and-its-frequency/241647/1 "2015-04-21T05:50:13Z")

</div>

hi,  
Im trying to find the frequency Offset between 2 USRPs then transmit my  
signal with compensating the Offset. From the forum I found out I can do  
this by transmit a cosinus signal and measure the peak and its  
frequency.

I could manually use file sink and put it into Matlab. But i want to  
build a “semi-automatic” System, that measure the Offset ,feed it into  
UHD Block, then send my own Signal.

Is there some way I can do this within GRC(very unlikely i think) or  
Python-Skript?

cheers