Re: [Discuss-gnuradio] How to get transmitted packet time in USRP?

[Josh Blum]

On 03/07/2013 09:19 PM, john jade wrote:
> Hi Josh,
> Thanks for the reply.Is there any sample example you could send me? I
> looked at the link it has nothing related to this.
> I want the code in python.
> Thanks
> 
> I have another doubt...
>  I just looked at tags_demo.cc example.In that code ,it has following lines
> 
>  const uhd::time_spec_t time_now = usrp_sink->get_time_now();
> 
>     boost::shared_ptr<tag_source_demo> tag_source =
> boost::make_shared<tag_source_demo>(
>         time_now.get_full_secs() + 1, time_now.get_frac_secs(), //time now
> + 1 second
>         samp_rate, idle_dur, burst_dur
>     );
> to get time.
> 1. Here TIME_NOW is mother board time or something else?

it was the time on the motherboard

> 2. What should i do if i have to get time in nanoseconds?

The time format of the tag is just a tuple of full and fractional seconds,

But if you are taking about that time_now, that was just to get an idea
of what time the device was on. You can read this value, or set it to a
known starting point like UTC. In any case, see the
uhd/types/time_spec.hpp, you can readily convert between that and
seconds if need be.

> 3.Is there any option to do it in python?
> 

Yes, tags can be created in python, I hope this is documented in the
blocks coding guide

Hope that helps!

> Thanks.
> 
> 
> On Fri, Mar 8, 2013 at 11:42 AM, Josh Blum <address@hidden> wrote:
> 
>>
>>
>> On 03/07/2013 06:38 PM, john jade wrote:
>>> Hi,
>>>
>>> I am using 2 USRPN210 devices one for transmitting and one for receiving
>>> and relaying it back to sender. I want time at which packet is
>> transmitted
>>> in both the devices.I am using benchmark_tx and bencmark_rx codes.
>>> please help me the code that i have to put...
>>>
>>
>> Actually, it works the other way around, you can control the time a
>> packet is transmitted using stream tags.
>>
>> A few good links about this section:
>>
>>
>> http://code.ettus.com/redmine/ettus/projects/uhd/wiki/GNU_Radio_UHD#Using-UHD-Software-with-GNU-Radio
>>
>> -josh
>>
>>> Thanks.
>>>
>>>
>>>
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