Re: [Discuss-gnuradio] Retune Request Time

[Richard Bell]

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 <address@hidden> 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 <address@hidden> 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

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