Hello Mohamed, I didn't consider the difference between baseband and passband bw, but isn't the difference by a factor two going in the wrong direction here?
If I assume that the PLL blocks want the bw defined as passband, when I get the signal out of the PLL blocks at baseband, I should see a bw that is half of the one I specified at passband, not twice it. If I assume that the PLL blocks want the bw defined as baseband, I should see no difference in bw. I'm still puzzled. Cheers, Daniele On 25/03/15 15:25, Mohamed ABOUZRAR wrote: > Hi Daniele, > > I'm quite sure that there is a miss understanding of the bandwidth > notion here, > Your first formula is certainly the right known one, so make sure you > use the baseband bandwidth, which is equal to half passband bw. > hope that helps. > > Regards, > Mohamed > > > > On Wed, Mar 25, 2015 at 2:09 PM, Daniele Nicolodi <dani...@grinta.net > <mailto:dani...@grinta.net>> wrote: > > Hello, > > the documentation for the PLL blocks in GNURadio says: "All settings > max_freq and min_freq are in terms of radians per sample, NOT HERTZ." > > Therefore I thought that to specify a bandwidth `bw` it would have to > converted from natural frequency units (Hz) into radians per sample with > something like: > > bw_rad_per_sample = bw * 2*pi / sampl_rate > > where `sampl_rate` is of course the sampling rate in Hz. > > However, looking at the PSD of the input and outputs to the PLL blocks, > it looks like my understanding is wrong and that the bandwidth should be > computed as > > bw_rad_per_sample = bw * pi / sampl_rate > > which differs from the former by a factor of 2. > > Is the documentation right, and my understanding of it wrong, or the > documentation is wrong? In the former case, I think it would be better > to clarify it a bit. > > Thanks! Cheers, > Daniele > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > -- > /*MSc, Supélec,*/ > /*Ingénieur d'Etat, INPT.*/ _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
