Re: [Discuss-gnuradio] Tuning the Rx board

[Eric Blossom]

On Sat, Jun 13, 2009 at 09:10:00PM -0400, Timur Alperovich wrote:
> Hi,
> 
> This should be pretty straightforward, but I couldn't
> descriptions/information about this anywhere. The db_basic_rx
> constructor looks like "db_basic_rx (usrp_basic_sptr usrp, int which,
> int subdev)".  I assume the "int which" parameter refers to the board
> index, but I'm not sure what "int subdev" refers to. Also, how does
> one look up the internal values assigned to these?

The daughterboards are automagically constructed for you.
You can access them using u->selected_subdev, or the lower-level db()
method.  I suggest filling in the usrp_subdev_spec structure and using
u->selected_subdev to retrieve a shared pointer to the daughterboard.

Use u->determine_rx_mux_value to calculate the appropriate
daughterboard specific mux value, then set the mux using set_mux.

Finally, tune using

  bool ok = u->tune(0, db, target_freq, &result)


See:

  http://gnuradio.org/doc/doxygen/classusrp__basic__rx.html
  http://gnuradio.org/doc/doxygen/classusrp__standard__rx.html
  http://gnuradio.org/doc/doxygen/group__usrp.html


> I'm messing with this because I'm trying to call the
> usrp_standard_rx::tune() function, to set the frequency, so I can
> avoid jumping through more hoops (i.e. not sure what else needs to be
> set to set the frequency properly, if using
> usrp_standard_rx::set_rx_freq() and figured this is a better way to do
> it all).
> 
> Thank you.
> 
> -- 
> Cheers,
> Timur

Eric