Forum: GNU Radio How to get transmitted packet time in USRP?

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...

Thanks.

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/w...

-josh

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?
2. What should i do if i have to get time in nanoseconds?
3.Is there any option to do it in python?

Thanks.

On 03/07/2013 09:19 PM, john jade wrote:
>
>     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!