On 12/18/2018 05:07 AM, Arun kumar Verma wrote:
Dear Marcus
I found the real problem and problem is that when i use
set_command_time in loop then only problem exist, if do not use this
my loop is getting executed properly. But for phase synchronization i
have to use set_command_time
Any suggestion?
Arun Verma
How rapidly is that loop executing? The timed-command queue is only 16
items deep, and you're scheduling at 0.01sec intervals.
------------------------------------------------------------------------
*From:* Arun kumar Verma via USRP-users <usrp-users@lists.ettus.com>
*To:* Marcus D. Leech <patchvonbr...@gmail.com>;
"usrp-users@lists.ettus.com" <usrp-users@lists.ettus.com>
*Sent:* Tuesday, 18 December 2018 2:16 PM
*Subject:* Re: [USRP-users] Phase Offset problem when center frequency
is changed dynamically
Dear Marcus
The problem is solved by setting RF policy manual for RF and DSP both
and passing uhd::tune_request_t object as parameter to set_center_freq
function, but now i getting one more issues that after 35-40 iteration
my application is getting assertion because of "EnvironmentError:
IOError: Block ctrl (CE_00_Port_30) no response packet -
AssertionError: bool(buff)" and after that I have to start X310 again
then only it responds.
My setup is X310 with single TwinRX module and I want to measure the
phase difference from 10-6000MHz and put into look-up table. I am
using B205-mini as transmitter and it is connected with the power
divider to X310 input. I am working on phase interferometer direction
finding with 5 element circular array antennae connected to 5 to 2
Antenna Switch matrix which is connected to single TwinRX.
I am not sure how set_center_freq command is implemented internally
for TwinRX, but i expect that when i set this command, only LOs should
be tuned for desired frequencies plus some filter selection of that
band. I expect that settling time for synthesizer would be around
maximum of 300uS and for some other stuff like filter selection , i
think in 500uS I should be able to set everything. At present I have
to use set_command_time so that my channels are synchronized. Can you
suggest the fastest way to implementing frequency sweep for two
channels as i need scan rate around 40GHz.
Regards,
Arun Verma
------------------------------------------------------------------------
*From:* Marcus D. Leech via USRP-users <usrp-users@lists.ettus.com>
*To:* usrp-users@lists.ettus.com
*Sent:* Monday, 17 December 2018 10:36 PM
*Subject:* Re: [USRP-users] Phase Offset problem when center frequency
is changed dynamically
On 12/15/2018 08:02 AM, Arun kumar Verma via USRP-users wrote:
Dear Users
I am facing problem of phase offset when i change center frequency
dynamically for TwinRX with X310 setup. Here is my C++ code,
Please advise
usrp_source1->set_rx_lo_source("internal",uhd::usrp::multi_usrp::ALL_LOS,0);
usrp_source1->set_rx_lo_source("companion",uhd::usrp::multi_usrp::ALL_LOS,1);
usrp_sourceDOA1->set_command_time(usrp_sourceDOA1->get_time_now() +
uhd::time_spec_t(0.01));
usrp_sourceDOA1->set_center_freq(m_CenterFrequency,0);
usrp_sourceDOA1->set_center_freq(m_CenterFrequency,1);
usrp_sourceDOA1->clear_command_time();
I feel set_command_time is not working properly. When i start the
X310 my phase difference is almost zero but as i change my frequency
pjhase difference is random in nature.
Regards,
Arun Verma
COuld you explain your setup a bit more here.
I now see that you have both usrp_source1 and usrp_sourceDOA1, but I
think you said that you have a single X310, so I'm confused about
why you apparently have two USRP sources here.
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