Hi Derek, Thank you for your email. If you could find that file it would be really helpful. What I want to do is to alternate between two or more values of gain after specific intervals. Can I alternate like this using the command port interface? How will the block USRP sink block know which value to use ? Can you kindly explain that a bit.
On Thu, Feb 23, 2017 at 4:23 PM, Derek Kozel <derek.ko...@ettus.com> wrote: > Hello, > > The command port interface can be used to change the gain value. There is > an example of creating messages for tuning included in gr-uhd. > https://github.com/gnuradio/gnuradio/blob/master/gr-uhd/ > examples/grc/uhd_msg_tune.grc > > I've used a function probe to generate coarsely timed "tick" messages to a > custom python block which is correctly formatting the messages before. > Unfortunately I cannot find that GRC file at the moment. The function probe > will run at an approximate interval dependent on your system and GNU > Radio's scheduler. If you don't need exact timing then just use the gain > message and function probe, if you do need exact timing include both time > and gain values in the pmt command message then the gain will be applied at > the specific time based on the radio timestamp. Set the Sync setting to > unknown_pps, which will set the radio timestamp to 0 when the flowgraph > starts, and set the initial timestamp for the command port message to a > second or two in the future to account for the startup time of the > flowgraph. > > Regards, > Derek > > On Thu, Feb 23, 2017 at 1:36 PM, Qurat-Ul-Ann Akbar < > quratulannakbar2...@u.northwestern.edu> wrote: > >> Hi, >> >> I want to alternate the gain of the USRP between two values after a >> certain period of time. For example after 100 ms it should go from A to B >> and after another 100 ms the value should go from B to A and so on. >> >> Is there an easy way of doing this in the GNU Radio companion or would I >> need to start a timer in python and put an IF condition to keep changing >> the value? Can I do this somehow using the probe block? >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> >
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