Also I want to keep doing this in a loop (the values keep alternating after an interval). Will it be possible through the command port interface ?
On Fri, Feb 24, 2017 at 9:17 AM, Qurat-Ul-Ann Akbar < quratulannakbar2...@u.northwestern.edu> wrote: > 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/exam >> ples/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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