# Phase between 2 channels drits

**URL:** <https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265>\
**Category:** LimeSDR\
**Created:** [19 July 2021 10:46 UTC](https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265 "2021-07-19T10:46:29Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![meo](https://avatars.discourse-cdn.com/v4/letter/m/c5a1d2/32.png) [@meo](https://discourse.myriadrf.org/u/meo)\
**Post date:** [19 July 2021 10:46 UTC](https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265/1 "2021-07-19T10:46:29Z")

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Hello,

I am using one LimeSDR with SDRangel and the phase between the two channels drifts.  
I have the same signal in both channels and the phase is not quiet.

Anyone know how to fix this issue?

Thanks,  
Mariana.

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**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [21 July 2021 10:26 UTC](https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265/2 "2021-07-21T10:26:28Z")

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This document may help:

> **[LimeSDR-USB\_channel\_alignment\_v01r00.pdf](https://github.com/myriadrf/LMS7002M-docs/blob/master/LimeSDR-USB_channel_alignment_v01r00.pdf)**

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**Author:** ![eldaromer](https://avatars.discourse-cdn.com/v4/letter/e/839c29/32.png) [@eldaromer](https://discourse.myriadrf.org/u/eldaromer)\
**Post date:** [21 July 2021 19:40 UTC](https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265/3 "2021-07-21T19:40:30Z")

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Hi @andrewback

I see this document getting referenced a lot. Is it possible to call this AlignRxRf function using the standard LimeSuite.h API that is available? Does setting the LMS\_ALIGN\_CH\_PHASE flag somehow call this function?

I’m just a little confused about how to actually get the channel alignment to happen through the C++ API

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**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [22 July 2021 08:54 UTC](https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265/4 "2021-07-22T08:54:56Z")

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I’m not familiar with the details, but someone in @Zack’s team may be able to advise.

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**Author:** ![meo](https://avatars.discourse-cdn.com/v4/letter/m/c5a1d2/32.png) [@meo](https://discourse.myriadrf.org/u/meo)\
**Post date:** [22 July 2021 16:31 UTC](https://discourse.myriadrf.org/t/phase-between-2-channels-drits/7265/5 "2021-07-22T16:31:56Z")

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Hi,

Thanks for your reply.

My problem is not just alignment it is worst. The phase from one channel drifts compared with the other channel. Looks like the NCOs are not synchronous. (Using SDRangel, working fine in all other aspects.)