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 delay==> 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
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