Wednesday, September 2, 2015

Re: [Discuss-gnuradio] USRP timing offset

Hi Leonard,

you should try to use set_start_time(time_spec_t(x)) on both the USRP sink and source, but only after setting a device time using set_time_now() before, that should be sufficiently (>0.1s) earlier than x, before you start the flow graph.

Best regards,
Marcus

On 02.09.2015 16:41, Leonard Foxes wrote:

Hi everyone!


I'm new to Gnuradio e USRP. I use a USRP N210 with WBX daughterboards and loop back cable to connect TX e RX. I have tested USRP with a simple flowgraph (sine , usrp_sink , usrp_source) and I have observed that the output signal from usrp_source block  is time shifted. I mean, the usefull output signal starts after 0.0105 seconds. How can avoid this? I have tried to use "issued_stream_cmd",  setting time_spec=0.0105 s but nothing has changed.


I want to use this USRP in a more complex project and I need to remove this initial time-shift.


I attach a plot of input and output signal and my flowgraph.


Thanks in advance for help,


Leo 



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