[USRP-users] Transmission with timestamps

Josh Blum josh at ettus.com
Mon Jun 4 12:42:42 EDT 2012



On 06/04/2012 01:55 AM, Matthias P. Braendli wrote:
> On 06/02/12 22:59, Josh Blum wrote:
>>> What is the best way to make the USRP reconsider the timestamps while
>>> the stream runs ? Is there a better way than dropping a packet, thereby
>>> creating an underrun ?
>>>
>> Basically, set the end of burst on the last TX packet.
>> Then send the next packet with a new time.
>>
>> The examples/tx_bursts.cpp should demonstrate this.
> 
> I cannot do an end of burst in regular intervals, because that always
> generates late packets. However, if I set EOB once when I have a
> discontinuity in my timestamps, it seems to be okay.
> 
> 

Excellent!

> How do I have to handle the async burst ACK packets ? And what do I gain
> by doing recv_async_msg() ? (Besides knowing that I had underruns or

You can ignore async messages, unless you find them useful :-)

If you are trying to push out TX samples as fast as possible, i
generally dont recommend waiting on async messages like burst ack in the
same thread.

> late packets, which is quite useful. If I check for underruns and late
> packets myself, can I suppress the printing of 'U' and 'L' to the console ?)
> 

http://files.ettus.com/uhd_docs/manual/html/general.html#disabling-or-redirecting-prints-to-stdout

-josh




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