# Frames and Channel names for O4 analysis

**URL:** https://ask.igwn.org/t/frames-and-channel-names-for-o4-analysis/863
**Category:** Data Analysis
**Created:** [December 18, 2023, 7:05pm UTC](https://ask.igwn.org/t/frames-and-channel-names-for-o4-analysis/863 "2023-12-18T19:05:16Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Alvin](https://avatars.discourse-cdn.com/v4/letter/a/b5a626/32.png) [@Alvin](https://ask.igwn.org/u/Alvin)
#### Post date: [December 18, 2023, 7:05pm UTC](https://ask.igwn.org/t/frames-and-channel-names-for-o4-analysis/863/1 "2023-12-18T19:05:16Z")

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Hi,

I am trying to go through the LIGO wiki page [DiscoveryService \< Main \< LIGOWiki](https://wiki.ligo.org/LSC/JRPComm/ObsRun4#OFFLINE_data_analysis_guide) and I would like to ask what is the difference (in terms of the data) between “AR” frames and normal frames? Which frame type should I use for doing O4 analysis? Many thanks in advance!

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### Author: ![jonah](https://yyz1.discourse-cdn.com/flex031/user_avatar/ask.igwn.org/jonah/32/10_2.png) [@jonah](https://ask.igwn.org/u/jonah)
#### Post date: [December 21, 2023, 11:07pm UTC](https://ask.igwn.org/t/frames-and-channel-names-for-o4-analysis/863/2 "2023-12-21T23:07:33Z")

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Hi @Alvin ! Thank you for posting this question.

During `ANALYSIS_READY` times, the “AR” and “C00” frames contain exactly the same strain values. The only difference between the two sets of frames is that the “C00” frames contain data at all times, while “AR” frames are only produced when an instrument passes `ANALYSIS_READY`.

For most offline analyses, you should use the AR frames if possible.