Hi We have a Setup with single x310 and 2 twinrx We use Ubuntu 16.04 linux; GNU C++ version 5.4.0 20160609; Boost_105800; UHD_3.11.0.1-0-ga1b5c4ae We have an Rx application We sync all channels(ch0-3) to ch0 lo. We use internal clock 1pps We are trying to sample 4 channels, each time for a defined period of time, Each time on a different frequency. We have issues syncing the channels and get strange results calculating phase difference
Case 1: We zero the time on each sample (not what we would ilke to do) We than get the same phase difference for a fixed frequency entered using a signal genrator gDevice->usrp()->set_time_unknown_pps(uhd::time_spec_t(0.0)); uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE); stream_cmd.num_samps = streamLength; stream_cmd.stream_now = false; stream_cmd.time_spec = uhd::time_spec_t(0.2); rx_stream->issue_stream_cmd(stream_cmd); case 2: uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE); stream_cmd.num_samps = streamLength; stream_cmd.stream_now = false; stream_cmd.time_spec = gDevice->usrp()->get_time_now() + uhd::time_spec_t(0.2); rx_stream->issue_stream_cmd(stream_cmd); on case 2 we get different phase phase difference on each recording, the phase difference is changing each time in +-(90/180/270) can you explain ? why does gDevice->usrp()->set_time_unknown_pps(uhd::time_spec_t(0.0)) need to get a fixed offset? Why if we don't do it we get +-(90/180/270) degrees ? This happens also if we wait for the next pps. What we would like to d0 As soon as we get a command - try and sample a define times for all channels This is done in a loop Can this be done differently? We tried continuous start stop with no success and also Thanks Ilay Software Team Leader This email and the associated attachments may contain information that is proprietary, privileged, confidential or otherwise protected from disclosure. If you are not the intended recipient or otherwise have received this message in error, you are not authorized to read, print, retain, copy or disseminate this message or any part of it. If you are not the intended recipient or otherwise have received this message in error, please notify me immediately, destroy any paper copies and delete all electronic files of the message. This email and the associated attachments may contain information that is proprietary, privileged, confidential or otherwise protected from disclosure. If you are not the intended recipient or otherwise have received this message in error, you are not authorized to read, print, retain, copy or disseminate this message or any part of it. If you are not the intended recipient or otherwise have received this message in error, please notify me immediately, destroy any paper copies and delete all electronic files of the message.
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