[USRP-users] different phase difference using splitter on each run

Marcus D. Leech patchvonbraun at gmail.com
Wed Mar 6 00:09:19 EST 2019


On 03/06/2019 12:06 AM, Koyel Das (Vehere) wrote:
>
> Okay so is it enough to use timed tuning to get constant phase 
> difference each time?
>
Assuming that all your streams are within the same multi_usrp object, 
coming from the same hardware device, yes, that should do it.

>
> Koyel Das
> Senior – Product Engineer
>
> Vehere | Proactive Communications Intelligence & Cyber Defence
> M: +919051132173 | T: +91 33 40545454 | F: +91 33 40545455 | W: 
> www.vehere.com <http://www.vehere.com/>/
> /
> /unnamed 
> <https://www.linkedin.com/company/vehere-interactive-p-ltd>unnamed (1) 
> <https://twitter.com/VehereIndia>unnamed (2) 
> <https://www.facebook.com/VehereIndia/>
>
> Vehere is the proud recipient of the Fastest Growing Technology 
> Company Awards in India & Asia since 2012!/
>
> The content of this e-mail is confidential and intended solely for the 
> use of the addressee. The text of this email (including any 
> attachments) may contain information, which is proprietary and/or 
> confidential or privileged in nature belonging to Vehere Interactive 
> Pvt Ltd and/or its associates/ group companies/ subsidiaries. If you 
> are not the addressee, or the person responsible for delivering it to 
> the addressee, any disclosure, copying, distribution or any action 
> taken or omitted to be taken in reliance on it is prohibited and may 
> be unlawful. If you have received this e-mail in error, please notify 
> the sender and remove this communication entirely from your system. 
> The recipient acknowledges that no guarantee or any warranty is given 
> as to completeness and accuracy of the content of the email. The 
> recipient further acknowledges that the views contained in the email 
> message are those of the sender and may not necessarily reflect those 
> of Vehere Interactive Pvt Ltd. Before opening and accessing the 
> attachment please check and scan for virus. WARNING: Computer viruses 
> can be transmitted via email. The recipient should check this email 
> and any attachments for the presence of viruses. The company accepts 
> no liability for any damage caused by any virus transmitted by this email.
> ------------------------------------------------------------------------
> *From:* Marcus D. Leech <patchvonbraun at gmail.com>
> *Sent:* Wednesday, March 6, 2019 10:14:56 AM
> *To:* Koyel Das (Vehere); 'USRP-users at lists.ettus.com'
> *Subject:* Re: [USRP-users] different phase difference using splitter 
> on each run
> On 03/05/2019 11:40 PM, Koyel Das (Vehere) wrote:
>>
>> Hi,
>>
>>
>> By tuning commands I understand you mean command of synchronization 
>> for frequency tuning? But then in which other places I have to use 
>> the timed commands like in gain, sample rate etc also do I have to 
>> use timed commands? If so what are those commands? I am not getting a 
>> clear example of this.
>>
>>
>> Regards,
>>
> The tuning commands are the critical ones--because, as I explained, 
> that's when the synthesizers are programmed, and the
>   "resynch" pulse has to happen at the same time, hence, timed tuning.
>
>
>>
>> Koyel Das
>> Senior – Product Engineer
>>
>> Vehere | Proactive Communications Intelligence & Cyber Defence
>> M: +919051132173 | T: +91 33 40545454 | F: +91 33 40545455 | W: 
>> www.vehere.com <http://www.vehere.com/>/
>> /
>> /unnamed 
>> <https://www.linkedin.com/company/vehere-interactive-p-ltd>unnamed 
>> (1) <https://twitter.com/VehereIndia>unnamed (2) 
>> <https://www.facebook.com/VehereIndia/>
>>
>> Vehere is the proud recipient of the Fastest Growing Technology 
>> Company Awards in India & Asia since 2012!/
>>
>> The content of this e-mail is confidential and intended solely for 
>> the use of the addressee. The text of this email (including any 
>> attachments) may contain information, which is proprietary and/or 
>> confidential or privileged in nature belonging to Vehere Interactive 
>> Pvt Ltd and/or its associates/ group companies/ subsidiaries. If you 
>> are not the addressee, or the person responsible for delivering it to 
>> the addressee, any disclosure, copying, distribution or any action 
>> taken or omitted to be taken in reliance on it is prohibited and may 
>> be unlawful. If you have received this e-mail in error, please notify 
>> the sender and remove this communication entirely from your system. 
>> The recipient acknowledges that no guarantee or any warranty is given 
>> as to completeness and accuracy of the content of the email. The 
>> recipient further acknowledges that the views contained in the email 
>> message are those of the sender and may not necessarily reflect those 
>> of Vehere Interactive Pvt Ltd. Before opening and accessing the 
>> attachment please check and scan for virus. WARNING: Computer viruses 
>> can be transmitted via email. The recipient should check this email 
>> and any attachments for the presence of viruses. The company accepts 
>> no liability for any damage caused by any virus transmitted by this 
>> email.
>> ------------------------------------------------------------------------
>> *From:* Marcus D. Leech <patchvonbraun at gmail.com> 
>> <mailto:patchvonbraun at gmail.com>
>> *Sent:* Wednesday, March 6, 2019 9:49:57 AM
>> *To:* Koyel Das (Vehere); 'USRP-users at lists.ettus.com 
>> <mailto:USRP-users at lists.ettus.com>'
>> *Subject:* Re: [USRP-users] different phase difference using splitter 
>> on each run
>> On 03/05/2019 11:17 PM, Koyel Das (Vehere) wrote:
>>>
>>> So basically I have to insert the following line
>>>
>>>
>>> usrp->set_command_time(cmd_time);
>>>
>>>
>>> before the code where I need timed operations and then at the end of 
>>> the code I insert
>>>
>>>
>>> usrp->clear_command_time();
>>>
>>>
>>> ??
>>>
>> The tuning commands in particular.
>>
>>
>>>
>>> Koyel Das
>>> Senior – Product Engineer
>>>
>>> Vehere | Proactive Communications Intelligence & Cyber Defence
>>> M: +919051132173 | T: +91 33 40545454 | F: +91 33 40545455 | W: 
>>> www.vehere.com <http://www.vehere.com/>/
>>> /
>>> /unnamed 
>>> <https://www.linkedin.com/company/vehere-interactive-p-ltd>unnamed 
>>> (1) <https://twitter.com/VehereIndia>unnamed (2) 
>>> <https://www.facebook.com/VehereIndia/>
>>>
>>> Vehere is the proud recipient of the Fastest Growing Technology 
>>> Company Awards in India & Asia since 2012!/
>>>
>>> The content of this e-mail is confidential and intended solely for 
>>> the use of the addressee. The text of this email (including any 
>>> attachments) may contain information, which is proprietary and/or 
>>> confidential or privileged in nature belonging to Vehere Interactive 
>>> Pvt Ltd and/or its associates/ group companies/ subsidiaries. If you 
>>> are not the addressee, or the person responsible for delivering it 
>>> to the addressee, any disclosure, copying, distribution or any 
>>> action taken or omitted to be taken in reliance on it is prohibited 
>>> and may be unlawful. If you have received this e-mail in error, 
>>> please notify the sender and remove this communication entirely from 
>>> your system. The recipient acknowledges that no guarantee or any 
>>> warranty is given as to completeness and accuracy of the content of 
>>> the email. The recipient further acknowledges that the views 
>>> contained in the email message are those of the sender and may not 
>>> necessarily reflect those of Vehere Interactive Pvt Ltd. Before 
>>> opening and accessing the attachment please check and scan for 
>>> virus. WARNING: Computer viruses can be transmitted via email. The 
>>> recipient should check this email and any attachments for the 
>>> presence of viruses. The company accepts no liability for any damage 
>>> caused by any virus transmitted by this email.
>>> ------------------------------------------------------------------------
>>> *From:* Marcus D. Leech <patchvonbraun at gmail.com> 
>>> <mailto:patchvonbraun at gmail.com>
>>> *Sent:* Wednesday, March 6, 2019 9:22:22 AM
>>> *To:* Koyel Das (Vehere); 'USRP-users at lists.ettus.com 
>>> <mailto:USRP-users at lists.ettus.com>'
>>> *Subject:* Re: [USRP-users] different phase difference using 
>>> splitter on each run
>>> On 03/05/2019 10:41 PM, Koyel Das (Vehere) wrote:
>>>>
>>>> The timed commands are as follows in rx_multisamples.cpp
>>>>
>>>>
>>>> if(sync=="now"){
>>>>
>>>> 	//This is not a true time lock, the devices will be off by a few RTT.
>>>>
>>>> 	//Rather, this is just to allow for demonstration of the code below.
>>>>
>>>> 	usrp->set_time_now(uhd::time_spec_t(0.0));
>>>>
>>>> 	}
>>>>
>>>> 	else if (sync == "pps"){
>>>>
>>>> 	usrp->set_time_source("external");
>>>>
>>>> 	usrp->set_time_unknown_pps(uhd::time_spec_t(0.0));
>>>>
>>>> 	boost::this_thread::sleep(boost::posix_time::seconds(1)); //wait 
>>>> for pps sync pulse
>>>>
>>>> 	}
>>>>
>>>> 	else if (sync == "mimo"){
>>>>
>>>> 	UHD_ASSERT_THROW(usrp->get_num_mboards() == 2);
>>>>
>>>> 	
>>>>
>>>> 	//make mboard 1 a slave over the MIMO Cable
>>>>
>>>> 	usrp->set_clock_source("mimo", 1);
>>>>
>>>> 	usrp->set_time_source("mimo", 1);
>>>>
>>>> 	
>>>>
>>>> 	//set time on the master (mboard 0)
>>>>
>>>> 	usrp->set_time_now(uhd::time_spec_t(0.0), 0);
>>>>
>>>> 	
>>>>
>>>> 	//sleep a bit while the slave locks its time to the master
>>>>
>>>> 	boost::this_thread::sleep(boost::posix_time::milliseconds(100));
>>>>
>>>> 	}
>>>>
>>>> 1. "now", 2 ."pps" and 3. "mimo"
>>>>
>>>> I was using "now" but still I don't get same phase difference in 
>>>> each run. Is there any other time command that I have to use or 
>>>> what do I have to set?
>>>>
>>>> Regards,
>>> Ah!  You have a misunderstanding about what I mean by "timed commands".
>>>
>>> See the "test_timed_commands" example in the source code tree.
>>>
>>> See also the documentation here:
>>>
>>> https://files.ettus.com/manual/page_sync.html
>>>
>>> Basically, you need to make sure that all the devices agree on what 
>>> time it is (if you have only one device, this is "easy").  Once you 
>>> have that,
>>>   THEN, you need to make sure that all the RF synthesizer tuning 
>>> happens at precisely the same instant, so that the re-synch feature
>>>   (if the device has one) can be triggered at exactly the same time.
>>>
>>> Without that, the synthesizers are free to "lock" at any phase-angle 
>>> with respect to the reference clock, and further the reference
>>>   divider in a synthesizer is guaranteed to be in the same state 
>>> across all synthesizers, even when they're using the same
>>>   reference clock.  This is what the "resynch" hardware signal is 
>>> all about, and what the set_command_time()/clear_command_time()
>>>   API is all about.
>>>
>>>
>>>
>>>
>>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20190306/cf8ebfc7/attachment.html>


More information about the USRP-users mailing list