# Xcvr2450 and MIMO

**URL:** <https://www.ruby-forum.com/t/xcvr2450-and-mimo/181819>\
**Category:** GNU Radio\
**Created:** [January 18, 2010, 9:55pm UTC](https://www.ruby-forum.com/t/xcvr2450-and-mimo/181819 "2010-01-18T21:55:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Per\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b38774/32.png) [@Per\_Z](https://www.ruby-forum.com/u/Per_Z)\
**Post date:** [January 18, 2010, 9:55pm UTC](https://www.ruby-forum.com/t/xcvr2450-and-mimo/181819/1 "2010-01-18T21:55:54Z")

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Dear All.

I think I read on the list that xcvr2450 doesn’t support MIMO (frequency  
coherent transceivers to be more precise). However, when I search for  
xcvr2450 and MIMO in the archives I don’t find any post on this.

Can somebody update me on this ?

BR/  
Per

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**Author:** ![Per\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b38774/32.png) [@Per\_Z](https://www.ruby-forum.com/u/Per_Z)\
**Post date:** [January 18, 2010, 11:14pm UTC](https://www.ruby-forum.com/t/xcvr2450-and-mimo/181819/2 "2010-01-18T23:14:22Z")

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On 01/18/2010 12:49 PM, Per Z. wrote:

> Dear All.
> 
> I think I read on the list that xcvr2450 doesn’t support MIMO (frequency  
> coherent transceivers to be more precise). However, when I search for  
> xcvr2450 and MIMO in the archives I don’t find any post on this.
> 
> Can somebody update me on this ?

You CAN do MIMO with the XCVR2450. However, phased arrays (where you  
need to know the absolute phase difference between boards) will be hard  
due to the fractional-N synthesizer.

The only board which is not MIMO capable is the TVRX.

Matt

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**Author:** ![Per\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b38774/32.png) [@Per\_Z](https://www.ruby-forum.com/u/Per_Z)\
**Post date:** [January 19, 2010, 6:26am UTC](https://www.ruby-forum.com/t/xcvr2450-and-mimo/181819/3 "2010-01-19T06:26:20Z")

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Matt E. wrote:

> You CAN do MIMO with the XCVR2450. However, phased arrays (where you  
> need to know the absolute phase difference between boards) will be  
> hard due to the fractional-N synthesizer.
> 
> The only board which is not MIMO capable is the TVRX.
> 
> Matt  
> That’s great! But doesn’t the same problem (fractional-N synthesizer)  
> also apply to the RFX? I think I have seen this phase-shift. I have used  
> my own db driver most of the time - does the proper driver fix this ?

BR/  
Per

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<div class="post-metadata">

**Author:** ![Per\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b38774/32.png) [@Per\_Z](https://www.ruby-forum.com/u/Per_Z)\
**Post date:** [January 20, 2010, 5:59am UTC](https://www.ruby-forum.com/t/xcvr2450-and-mimo/181819/4 "2010-01-20T05:59:57Z")

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On 01/18/2010 09:23 PM, Per Z. wrote:

> > You CAN do MIMO with the XCVR2450. However, phased arrays (where you  
> > need to know the absolute phase difference between boards) will be  
> > hard due to the fractional-N synthesizer.
> > 
> > The only board which is not MIMO capable is the TVRX.
> > 
> > Matt  
> > That’s great! But doesn’t the same problem (fractional-N synthesizer)  
> > also apply to the RFX? I think I have seen this phase-shift. I have used  
> > my own db driver most of the time - does the proper driver fix this ?

There will be a phase ambiguity with all the PLLs, but there is a small  
number of possible phase differences with an integer-N PLL (roughly  
equal to the R-divider), while there are thousands with a fractional-N.

Matt