[USRP-users] time sync 2 ettus x310

Michael West michael.west at ettus.com
Fri Apr 24 08:56:34 EDT 2015


Hi Sanjoy,

Go to the top of the UHD source directory and type "git apply <patch>".
Then follow the instructions to build and install from the source:

http://files.ettus.com/manual/page_build_guide.html

(In Linux, it should be as simple as navigating to the UHD build directory
and typing "sudo make install".)

Regards,
Michael

On Fri, Apr 24, 2015 at 5:10 AM, Sanjoy Basak <sanjoybasak14 at gmail.com>
wrote:

> Dear Mr. Michael,
> I have a stupid question. I don't really know how to apply the patch
> files. I tried different ways to apply, but none of those worked well. I
> tried with 'apply patch 'filename'' or git patch 'filename' on terminal;
> but could not make it work.
> I am actually using python file to operate usrp or simply with grc.
> Could you please tell me how to apply the patch file now or what exactly I
> need to modify with python? or what exactly I need to do.
> Please let me know.
>
> best regards
> Sanjoy
>
> On Wed, Apr 22, 2015 at 5:48 PM, Michael West <michael.west at ettus.com>
> wrote:
>
>> Hi Sanjoy,
>>
>> I have attached the UHD patch that changes the ATR settings at the idle
>> state to always enable frontend components for SBX and CBX daughter
>> boards.  Give it a try and let us know if it works for you.
>>
>> Regards,
>> Michael
>>
>> On Wed, Apr 22, 2015 at 2:36 AM, Sanjoy Basak <sanjoybasak14 at gmail.com>
>> wrote:
>>
>>> Dear Mr. Michael,
>>> Thank you very much for the reply. I am putting all the information here
>>> regarding usrp.
>>>
>>> daughter board: SBX-120
>>> UHD version: UHD_003.008.002-80-ge28d7844
>>>
>>> I am attaching here a pdf which includes all other information of the
>>> usrp. Please send me the patch and other instruction and suggestion.
>>> Have a nice day.
>>>
>>> best regards
>>> Sanjoy
>>>
>>>
>>> On Wed, Apr 22, 2015 at 2:29 AM, Michael West <michael.west at ettus.com>
>>> wrote:
>>>
>>>> Hi Sanjoy,
>>>>
>>>> The distortion may be due to the fact that some frontend components are
>>>> disabled or powered down while not transmitting or receiving and take a
>>>> little time to settle when enabled or powered up.  For the X310, there are
>>>> 3 ways around this:
>>>>
>>>> 1)  Start TX and RX earlier and throw away RX data (as you have done)
>>>> 2)  Modify ATR settings dynamically so the frontend components stay
>>>> powered on and enabled.  This can be done by using the
>>>> multi_usrp::set_gpio_attr() method.  The banks are RX0, RX1, TX0, and TX1.
>>>> You can accomplish this by adding the following lines to your code:
>>>>     usrp->set_gpio_attr("RX0", "ATR_0X", usrp->get_gpio_attr("RX0",
>>>> "ATR_XX", 0), ~0, 0);
>>>>     usrp->set_gpio_attr("RX1", "ATR_0X", usrp->get_gpio_attr("RX1",
>>>> "ATR_XX", 0), ~0, 0);
>>>>     usrp->set_gpio_attr("TX0", "ATR_0X", usrp->get_gpio_attr("TX0",
>>>> "ATR_XX", 0), ~0, 0);
>>>>     usrp->set_gpio_attr("TX1", "ATR_0X", usrp->get_gpio_attr("TX1",
>>>> "ATR_XX", 0), ~0, 0);
>>>>     usrp->set_gpio_attr("RX0", "ATR_0X", usrp->get_gpio_attr("RX0",
>>>> "ATR_XX", 1), ~0, 1);
>>>>     usrp->set_gpio_attr("RX1", "ATR_0X", usrp->get_gpio_attr("RX1",
>>>> "ATR_XX", 1), ~0, 1);
>>>>     usrp->set_gpio_attr("TX0", "ATR_0X", usrp->get_gpio_attr("TX0",
>>>> "ATR_XX", 1), ~0, 1);
>>>>     usrp->set_gpio_attr("TX1", "ATR_0X", usrp->get_gpio_attr("TX1",
>>>> "ATR_XX", 1), ~0, 1);
>>>> *Note that changing the antenna or gain settings may overwrite these
>>>> values.
>>>> 3)  Modify ATR settings in UHD code.  This is done by editing the UHD
>>>> code for the specific daughter board to change the ATR settings.
>>>>
>>>> Option #3 is the one that has worked the best for most users.  If you
>>>> let me know what daughter card and UHD version you are using, I may be able
>>>> to provide you with a UHD patch.
>>>>
>>>> Regards,
>>>> Michael
>>>>
>>>>
>>>>
>>>> On Tue, Apr 21, 2015 at 1:34 AM, Sanjoy Basak via USRP-users <
>>>> usrp-users at lists.ettus.com> wrote:
>>>>
>>>>> Dear Mr. Martin,
>>>>> Thanks for the reply. Yes, right now I am not using octoclock, so the
>>>>> problem while using 2 USRPsis understandable.
>>>>>
>>>>> However, regarding distortion, yes I am having distortion at the
>>>>> beginning when I am using one usrp  for SISO case for x310. I found this
>>>>> problem even in b210 as well. I wonder why no one discussed or how did they
>>>>> actually solved for radar uses. But I hope I would get my solution here.
>>>>>
>>>>>
>>>>> [image: Inline image 1]
>>>>> This is a figure of xcorr of rx and tx signal. The red marked
>>>>> distortion I am having almost always. I don't know the reason. If I drop
>>>>> few bins in my binary file and then start receiving my signal then I am
>>>>> getting an undistorted signal looks like the following.( I am transmitting
>>>>> and receiving using binary file).
>>>>> However, dropping bins is undesirable for radar application.
>>>>> [image: Inline image 3]
>>>>> If I use the distorted frame, as obvious I get distorted result.
>>>>> However, after dropping bins the fresh frame gives me the exact result
>>>>> after signal processing in matlab.
>>>>> Can you please tell me how to avoid this distortion at the beginning?
>>>>>
>>>>> best regards
>>>>> Sanjoy
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Apr 21, 2015 at 12:10 AM, Martin Braun via USRP-users <
>>>>> usrp-users at lists.ettus.com> wrote:
>>>>>
>>>>>> Sanjoy,
>>>>>>
>>>>>> if you want to do radar, you need to make sure both devices are
>>>>>> connected to the same external reference. For radar, you can't run off
>>>>>> of separate clocks.
>>>>>>
>>>>>> We've confirmed timing accuracy across devices on the nanosecond scale
>>>>>> in the past (using OctoClocks for clock distribution).
>>>>>>
>>>>>> Cheers,
>>>>>> M
>>>>>>
>>>>>> On 17.04.2015 06:00, Sanjoy Basak via USRP-users wrote:
>>>>>> > Hi all,
>>>>>> > I am trying to sync 2 ettus x310 in time. However, I am always
>>>>>> having a
>>>>>> > distortion at the beginning after receiving, and there is always a
>>>>>> > delay of few microseconds between the tx and rx. I put tx in one
>>>>>> x310
>>>>>> > and rx in another x310 and its in a wired connection. GPS antenna is
>>>>>> > connected to one usrp(with Tx) and another one is on external
>>>>>> ref(Rx).
>>>>>> >
>>>>>> > So now if I check the last pps on both usrp; it shows tx:0; rx:2s;
>>>>>> > then I am compensating it making it set_start_time both at for 4s.
>>>>>> So
>>>>>> > ideally I should get time synced tx and rx signal.
>>>>>> >
>>>>>> > But I am getting distortion in Rx signal for 2seconds at the
>>>>>> beginning;
>>>>>> > this is constant for every sampling freq; so if in that region I
>>>>>> have my
>>>>>> > rx signal I can't retrieve that as the distortion is already
>>>>>> introduced
>>>>>> > there.
>>>>>> > As I am trying to implement radar with x310, this is a serious
>>>>>> problem
>>>>>> > for me. As within first 2 seconds and few microseconds I can't
>>>>>> receive
>>>>>> > anything.
>>>>>> >
>>>>>> > I would really appreciate any kind of suggestion that come through.
>>>>>> If
>>>>>> > anyone have question regarding setup or python code please ask.
>>>>>> > Thanks for reading.
>>>>>> >
>>>>>> > Best regards
>>>>>> > Sanjoy
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> > _______________________________________________
>>>>>> > USRP-users mailing list
>>>>>> > USRP-users at lists.ettus.com
>>>>>> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>>>>> >
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> USRP-users mailing list
>>>>>> USRP-users at lists.ettus.com
>>>>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> USRP-users mailing list
>>>>> USRP-users at lists.ettus.com
>>>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>>>>
>>>>>
>>>>
>>>
>>
>
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