On 08/16/2020 12:46 PM, Koyel Das (Vehere) wrote:
The measurement is not initial phase but the phase difference between
two channels
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Are you using an external reference, or using the internal clock in the
X310?
If you observe an individual channel, is it "sane" ? That is,
apparently on-frequency, and with correct amplitudes and low distortion?
------------------------------------------------------------------------
*From:* Koyel Das (Vehere) <[email protected]>
*Sent:* Sunday, August 16, 2020 10:15:48 PM
*To:* Marcus D. Leech <[email protected]>;
[email protected] <[email protected]>
*Subject:* Re: [USRP-users] Incorrect data from usrp 2955
the phase difference between two channels of USRP as a function of
frequency and time, when measured by splitting the same signal and
feeding two channels of usrp, are wandering around wrt one another
which was not happening before. I had given demo more than 30 times
based on this principle and tested previously more than 50 times and I
got correct result every time. Now only suddenly it started happening.
The frequency is 2.4 GHz and bandwidth I tried from 1 MHz to 100 MHz.
Previously the whole bandwidth was showing similar values but then
suddenly started behaving abnormally giving near to correct result
sometimes and sometimes junk.
Regards,
Koyel
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*From:* Marcus D. Leech <[email protected]>
*Sent:* Sunday, August 16, 2020 10:05 PM
*To:* Koyel Das (Vehere); [email protected]
*Subject:* Re: [USRP-users] Incorrect data from usrp 2955
On 08/15/2020 11:59 PM, Koyel Das (Vehere) wrote:
No it doesn’t look better again after reducing gain. Sometimes the
phase differences are closeby but not so same as we were getting
before and most of the times they are totally incorrect. Strength of
the signal when we tried with maximum gain was near -40 dbm.
Regards,
Koyel
To clarify some things.
(A) The phase errors are just the initial phases--they don't wander
around with respect to one another during a run?
(B) What frequency range?
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------------------------------------------------------------------------
*From:* USRP-users <[email protected]>
<mailto:[email protected]> on behalf of Marcus D.
Leech via USRP-users <[email protected]>
<mailto:[email protected]>
*Sent:* Sunday, August 16, 2020 12:25:37 AM
*To:* [email protected] <mailto:[email protected]>
<[email protected]> <mailto:[email protected]>
*Subject:* Re: [USRP-users] Incorrect data from usrp 2955
On 08/15/2020 01:16 PM, Koyel Das (Vehere) via USRP-users wrote:
Hi,
We are using USRP 2955. Something has gone wrong. Before we were
getting constant phase difference across channels for limited
bandwidth and with time when we split single antenna signal using
splitter and fed two channels of USRP but now it is not doing so.
This happened on Friday that after getting a series of correct
results : constant phase difference across channels by feeding
signal using splitter as mentioned above, we suddenly started to
receive wrong data: random phase across channels and with time
using the same setup with splitter. The thing we did was setting
gain to near maximum and receiving 100 MHz sample rate. But I don't
think amplifier has damaged because in this usrp we have four
independent channels and when we connected the splitter to unused
channels then also we got wrong data. What can go wrong that USRP is
streaming data but phases are wrong? What do you think? Please let
me know.
Regards,
Koyel
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Does it look better again when you reduce the gain?
What is the magnitude of the signals going to the RX ports?
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