Re: [Discuss-gnuradio] Retune Request Time

[Martin Braun]

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 <address@hidden
> <mailto: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 <mailto: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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> 
> 
> 
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