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_timeAny
suggestion?
Arun Verma
From: Arun kumar Verma via USRP-users <[email protected]>
To: Marcus D. Leech <[email protected]>; "[email protected]"
<[email protected]>
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 <[email protected]>
To: [email protected]
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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