Re: [Discuss-gnuradio] USRP transmitting timestamp

[Marcus Müller]

Hi Chun Huai Du,

> I think that is a packed based transmitting.
The semantic differentiation between frame and packet is not very sharp,
especially between computer scientists and radio communication
engineers, so I think you're right!
> is there any method to get the transmitting timestamp of USRP sink?
Setting it. There's no later method of getting that, as far as I know.

> to make the stream continuous and i can get the valid timestamp.

I think you're on to something good :)
You set the time of the first sample you transmit, you can deduct the
later samples' times simply by (sample count)/(sampling rate) if you
continously send samples.

You can set the time where the first sample is sent using the
usrp_sink's "set_start_time" method.

> but if my flow is not continuous...
Then, you should specify the timestamp for each packet.


Best regards,
Marcus

On 07/10/2015 07:53 PM, ChunHuai Fu wrote:
> hi,
>
> I want to transmit a frame from a USRP to another USRP.
>
> I think that is a packed based transmitting.
>
> is there any method to get the transmitting timestamp of USRP sink?
>
> I check the usrp_sink_impl.cc.
>
> there is the "_metadata.time_spec", it will update by the num_sent and
> the samp_rate.
>
> but if my flow is not continuous...
>
> so that the time is invalid... due to the time not keep updating.
>
> or  is there any method about making the frame along with a continuous
> stream?
>
> to make the stream continuous and i can get the valid timestamp.
>
> Thank you so much!!
>