# Recording external events timestamps

**URL:** <https://www.ruby-forum.com/t/recording-external-events-timestamps/234848>\
**Category:** GNU Radio\
**Created:** [November 27, 2014, 1:53pm UTC](https://www.ruby-forum.com/t/recording-external-events-timestamps/234848 "2014-11-27T13:53:51Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [November 27, 2014, 1:53pm UTC](https://www.ruby-forum.com/t/recording-external-events-timestamps/234848/1 "2014-11-27T13:53:51Z")

</div>

Hello,

I have an application where I acquire and process data through GNURadio  
while I modify some system parameters via slow controls (USB, GPIB, or  
network interfaces) handled in a separate python thread.

I would like to be able to relate the data saved by the GNURadio flow  
graph execution to the external parameters changes. What is the best way  
of achieving this?

I can think to a few possible solutions: one possibility could be to  
extract sample timing from the GNURadio data stream at the time of the  
parameters change and record it independently, another could be to  
inject tags into the GNURadio data stream. In both cases I don’t really  
know how the implementation would look like.

Ideas?

Thanks. Cheers,  
Daniele