Hi Claude, there's only one FIFO per radio.
"Tags" is a GNU Radio concept. GNU Radio's USRP blocks take these tags and messgaes, and issue UHD tune_request. So, yes, in the end, there's only one way to tune, and that goes through a FIFO. Best regards, Marcus On Thu, 2017-12-21 at 11:35 +0100, LEMENAGER Claude via USRP-users wrote: > Hello, > As no answer received, and after an (not in depth) analysis of > USRP_SINK, USRP_SOURCE, I found: > - Dsp_freq and lo_freq message were associated with > POLICY_MANUAL on the other parameter (then, when a dsp_treq message > is issued, a full tuning of analog board is performed) > - On the TX part when a tx_freq tag is issued with a tx_sob tag > and a tx_time tag at the first sample of a sample set, the tx_freq is > performed immediately without respect of the buffering, resulting in > a tune before the asked time. > Just two questions: > Is there just one FIFO (TX and RX in the same) for timed commands or > two FIFOs (allowing no fine control of the time between commands to > RX and TX)? > RX tuning is performed through messages as TX tuning can be done > through tags. Does implementation (when timing is required) goes > through the FIFO(s) to perform the operation? > > Regards, > Claude > ========== > Hello, > > I try to send frequency radio tuning commands to TX (USRP_SINK) and > RX (USRP_SOURCE) in the same Gnu Radio companion design using the > same usrp (N210 or X310 for TX and RX. > The USRP_SINK block is feed by a stream which has tags tx_eob and > tx_sob associated with tx_time and tx_freq tags (are tx_lo_freq and > tx_dsp_freq usable)?. > The URSP_SOURCE receives “command” message with time and dsp_freq, > lo_freq keys and pmt values. > The time key of the USRP_SOURCE message has a value delayed > (adjustable ) with respect of tx_time tagged in the stream of > USRP_SINK. > I can check that, without RX command, TX is OK (external scope and > specrum analyzer) > That’s not the case when I issue the commands to RX, even when I > sleep the delay to send the message and L characters appear (late > command error seen by UHD, more delayè more L). > Remembering that the FIFO of timed command of is common for the board > (no TX or RX specific FIFO) the question is : > how to avoid discrepancy in the time between TX stream (or PDU-tagged > stream Block) and RX commands? (I think my RX command arrives in the > FIFO before the tx_sob/tx_freq tag) > > is it possible to put a tx_freq tag with a tx_eob tag on a stream (is > then the lo prepositioned?)? > > Excuse me is somebody asked about the same problem before (I don’t > find tracks about that). > > Can anybody help? > > Thanks for support > > Claude Leménager > > _______________________________________________ > USRP-users mailing list > [email protected] > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com _______________________________________________ USRP-users mailing list [email protected] http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
