Martin and Derek, Thank you. That is much more clear to me now.
Rich On Tue, Jun 14, 2016 at 1:19 PM, Martin Braun <martin.br...@ettus.com> wrote: > On 06/13/2016 04:47 PM, Richard Bell wrote: > > I can call the C++ functions from Python? Why is there a separate python > > API, I'm confused. > > It's the same API, SWIG exposes that to Python. > > > Lets say I set an initial center frequency of 900 MHz to start the > > script off. You're saying that if the next frequency I want to hop to is > > within the ADC sampling rate, which in my case for the N210 is 100 MHz, > > I should manually tell the USRP to set the DSP_FREQ and leave the > > RF_FREQ alone for the fastest hop, and that the USRP automatic settings > > are not smart enough to figure this out? > > What I'm saying is, there are no automatic settings other than fixing > the limited accuracy of the RF frequency using the DSP. > The tune logic is mostly stateless (with the exception of the > calibrations on the AD9361-based devices). > > > If the above is true, it seems I should do something like this: > > 1) Ask the USRP what the current RF_FREQ is > > 2) Find the difference between RF_FREQ and the new center freq > > 3) If the difference is greater then 100 MHz, change the RF Freq, > > otherwise change the DSP freq > > > > Is this correct? > > Yup. > > M > > > > > On Mon, Jun 13, 2016 at 4:03 PM, Martin Braun <martin.br...@ettus.com > > <mailto:martin.br...@ettus.com>> wrote: > > > > Richard, > > > > "use DSP tuning when possible" is not a valid policy. > > > > In Python: > > > > from gnuradio import uhd > > > > rf_freq = 900e6 > > dsp_freq = 1e3 > > TR = uhd.tune_request(rf_freq, dsp_freq) > > # Oh look it worked: > > print TR.rf_freq_policy == uhd.tune_request.POLICY_MANUAL > > > > > > So, in a nutshell, rf_freq and dsp_freq are used depending on the > > respective policies, but there's no 'figure out smart tunes based on > > state' policy. > > > > -- M > > > > > > On 06/13/2016 03:49 PM, Richard Bell wrote: > > > Derek, > > > > > > that manual is the C++ API. How would I format the tune policy > > > information in python? It's not clear to me looking at the C++ API > and > > > the Python API for the set_center_freq python function. Could you > give > > > an example of how you would call > > > > > > C++: > http://files.ettus.com/manual/structuhd_1_1tune__request__t.html > > > Python: > > > > http://www.gnuradio.org/doc/sphinx/uhd_blocks.html#gnuradio.uhd.usrp_sink > > > > > > set_center_freq(center_freq, <USE_DSP_TUNING_WHEN_POSSIBLE>) > > > > > > What goes in place of the careted argument? > > > > > > Rich > > > > > > On Mon, Jun 13, 2016 at 3:31 PM, Derek Kozel < > derek.ko...@ettus.com <mailto:derek.ko...@ettus.com> > > > <mailto:derek.ko...@ettus.com <mailto:derek.ko...@ettus.com>>> > wrote: > > > > > > Hi Rich, > > > > > > You can create and pass a tune_request_t into the set > frequency call > > > of a USRP object. This gives you control of how it tunes. By > default > > > it does not optimize for speed to my knowledge. > > > > http://files.ettus.com/manual/structuhd_1_1tune__request__t.html > > > > > > Depending on what USRP you are using there are self calibration > > > thresholds which will cause a retune to incur a delay when > tuning > > > outside of a certain range. On the B200 for instance this > range is > > > 100MHz. > > > > > > Regards, > > > Derek > > > > > > On Mon, Jun 13, 2016 at 3:05 PM, Richard Bell > > > <richard.be...@gmail.com <mailto:richard.be...@gmail.com> > > <mailto:richard.be...@gmail.com <mailto:richard.be...@gmail.com>>> > > wrote: > > > > > > I am using set_center_freq(center_freq) in my python > script to > > > retune my USRP to various center frequencies. Does this > command > > > use the smartest retune technique to get to the new > frequency? > > > > > > For example, if I want to retune from 900.000 MHz to > 900.001 MHz > > > ( a 1 kHz change), will it use DSP tuning instead of RF > tuning > > > for speed? Is there a way to control this through python? > > > > > > In my testing, it seems the retune time is constant > whether I > > > make a 1 GHz hop, a 3 MHz hop or a 1 kHz hop, which makes > me > > > think I'm overlooking something. > > > > > > Thanks, > > > Rich > > > > > > _______________________________________________ > > > Discuss-gnuradio mailing list > > > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > > <mailto:Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org>> > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > > > > > > > > > > _______________________________________________ > > > Discuss-gnuradio mailing list > > > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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