On 01/28/2020 05:53 AM, Sourin Mondal (Vehere) wrote:
Hi Marcus,
I think my previous email is not sent properly so sending again.
Thanks for the information you provided. This 5 degrees is for what
frequency? Are you sure its 5 degrees or less? What is the precision?
Regards,
Sourin
The component of phase offset from the synthesizers should be small,
after a phase-reset using timed-command tuning, irrespective of
frequency. Other components of phase offset, such as differential
heating effects, wiring-length differences, etc, will have a
frequency-sensitive component.
------------------------------------------------------------------------
*From:* Marcus D. Leech <patchvonbr...@gmail.com>
*Sent:* Monday, January 27, 2020 11:54 AM
*To:* Sourin Mondal (Vehere) <sourin.mon...@vehere.com>
*Cc:* usrp-users@lists.ettus.com <usrp-users@lists.ettus.com>
*Subject:* Re: [USRP-users] phase-aligning two USRPs without Octoclock
On 01/27/2020 01:00 AM, Sourin Mondal (Vehere) wrote:
Hi Marcus,
Thanks for the information. Could you please also tell what is the
accuracy with which the phases are aligned between USRP channels,
when we use 10 MHz reference to align, in pico-seconds or nano-seconds?
Regards,
Sourin
The answer to that question depends very much on the hardware involved.
In general, two synthesizers locked to the same clock won't have a
zero phase *offset* from one another, but will be phase-coherent
on an ongoing basis.
Now, for *some* types of Ettus hardware, there is special hardware
that can arrange to phase-reset during tuning, so that all the
participating
synthesizers will have small phase-offsets with respect to one another.
We generally talk in terms of degrees, rather than picoseconds or
nanoseconds. Residual phase offsets will typically be under 5 degrees.
But keep in mind that things like differential heating of cables, and
internal circuit in ANY coherent radio can case the phase relationships
to drift slightly.
------------------------------------------------------------------------
*From:* Marcus D. Leech <patchvonbr...@gmail.com>
<mailto:patchvonbr...@gmail.com>
*Sent:* Thursday, January 23, 2020 12:48 PM
*To:* Sourin Mondal (Vehere) <sourin.mon...@vehere.com>
<mailto:sourin.mon...@vehere.com>
*Subject:* Re: [USRP-users] phase-aligning two USRPs without Octoclock
On 01/22/2020 11:53 PM, Sourin Mondal (Vehere) wrote:
Hi Marcus,
Do I need to use 1 PPS also along with 10 MHz reference? And are
there any software commands to be used along with these hardware
configuration for synchronizing multiple USRPs without octoclock? If
so what are those commands?
Regards,
Sourin
You would do well to spend some time with this app-note:
https://kb.ettus.com/Synchronization_and_MIMO_Capability_with_USRP_Devices
Indeed, there are many app-notes that might be relevant for you.
Along with:
http://files.ettus.com/manual/
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