# Synchronization between two E100 devices

**URL:** <https://www.ruby-forum.com/t/synchronization-between-two-e100-devices/212232>\
**Category:** GNU Radio\
**Created:** [September 26, 2011, 5:53pm UTC](https://www.ruby-forum.com/t/synchronization-between-two-e100-devices/212232 "2011-09-26T17:53:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\
**Post date:** [September 26, 2011, 5:53pm UTC](https://www.ruby-forum.com/t/synchronization-between-two-e100-devices/212232/1 "2011-09-26T17:53:59Z")

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Hi everyone,

I’m trying to synchronize two E100 devices, both connecting to the  
ethernet. According to the Synchronization Application Notes of UHD,  
there are a couple of methods to do it. But the problem is that I don’t  
have access to either an external GPSDO or a reference clock signal.

I tried to access both devices by providing the IP address of  
uhd\_usrp\_source/sink, then set the time of them using the set\_time\_now()  
method. But it turned out that another m’board is not accessible to the  
host device.

So I was wondering, under this circumstances, is there a way to  
synchronize the device time of two E100s?

Thanks in advance,

Terry

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**Author:** ![ziyang](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/8c91f0/32.png) [@ziyang](https://www.ruby-forum.com/u/ziyang)\
**Post date:** [September 26, 2011, 7:01pm UTC](https://www.ruby-forum.com/t/synchronization-between-two-e100-devices/212232/2 "2011-09-26T19:01:28Z")

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On Mon, Sep 26, 2011 at 8:52 AM, ziyang [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> device.
> 
> So I was wondering, under this circumstances, is there a way to synchronize  
> the device time of two E100s?

If you need them to be truly synchronized, then the only way to do it  
is by distributing an accurate PPS and 10MHz reference to them.  
Issuing set\_time\_now() “simultaneously” to two devices will get you  
within some microseconds, but not synchronize them at the sample  
level.

–n

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**Author:** ![ziyang](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/8c91f0/32.png) [@ziyang](https://www.ruby-forum.com/u/ziyang)\
**Post date:** [September 26, 2011, 7:18pm UTC](https://www.ruby-forum.com/t/synchronization-between-two-e100-devices/212232/3 "2011-09-26T19:18:10Z")

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Hi Nick,

Thanks for your reply. In my application, a microsecond-order accuracy  
will be enough for the synchronization right now. But I didn’t manage to  
issue set\_time\_now() to the other usrp because it seems only the usrp of  
the host device is accessible. So I was wondering if there is a way to  
access another e100 from the host device?

Thanks,

Terry