On 11/07/2018 09:31 PM, Serge Malo wrote:
Yes:
We only use one streamer for all RF outputs, and send time_spec with
each call to the streamer's send method.
We reset the internal time with set_time_unkown_pps(0), and program
the first samples to be streamed at a time of 0.800s.
It is basically the same code we used on the X300/X310.
Thanks,
Serge
Well, that is quite strange--the magnitude of the time offsets is larger
than I would expect.
Perhaps someone from the N310 team can comment?
Serge, are you using the latest UHD and system image versions for the N310?
On Wed, 7 Nov 2018 at 21:03, Marcus D. Leech via USRP-users
<usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>> wrote:
On 11/07/2018 08:53 PM, Serge Malo via USRP-users wrote:
Hi all,
We are trying to send 4 synchronous signals from the 4 Tx ports
of the N310.
We are using UHD 3.13.1.0 RC1 under Ubuntu.
Central Freq = 1575.42 GHz and 1227.6 MHz
Master Clock rate = 153.6 MHz
We would expect to have less than 3ns offset between all TX ports
of the N310, like we do with the X300/X310. However, we have
measured 4700ns between TX RF ports 0 and port 2.
We have tried the next things with no more success:
- Sampling rates of 25.6MSps, 38.4Msps, 76.8Msps
- Init with the device options "init_cals=ALL" and "force_reinit=1"
- Use the internal GPSDO
- Use clock_source=external and time_source=external (from an
Octoclock).
Can you tell us:
-What time offset between TX RF ports we should expect to achieve?
-Is there anything else we can try to reduce this offset to less
than 3ns?
Best regards,
Serge
How are you setting up your TX streamer? Is it time-tagged to
start at a particular device time?
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