Re: [Discuss-gnuradio] Is there a way to grab the bandwidth of the daughterboard?

[Eric Blossom]

On Thu, Aug 06, 2009 at 04:45:32PM -0400, Jonathan Coveney wrote:
> I'm creating a new fm demodulator based on usrp_rx_nogui, and in the
> interest of modularity I'd like to grab the width of frequency being
> captured off the daughterboard (in my case the TVRX, which I think is about
> 6MHz?)
> 
> in an fm example I've been referring to, for example, you do this:
> 
>     # set front end gain
>     rf_front_end.set_AGC (300)
>     IF_freq = rf_front_end.get_output_freq ()
>     IF_freq = 5.75e6
> 
> but obviously even there they hardcode the IF_freq. Is there anything I can
> do, or should I just hardcode it, and add an option letting people change
> it?

I suggest you start with gnuradio-examples/python/usrp/usrp_wfm_rcv_nogui.py.

In general there's no need to know the center of the IF coming off
of the daughterboard.  u.tune(...) does the right thing and translates
your desired frequency to baseband (0 Hz).

There's currently no way to query for the usable IF bandwidth of any
of the daughterboards.  You are correct in that the usable bandwidth
on the TVRX is about 6 MHz.

Eric