Thanks MB. On Fri, Mar 4, 2011 at 9:51 AM, Martin Braun <[email protected]> wrote:
> On Fri, Mar 04, 2011 at 08:51:28AM -0500, Nick Othieno wrote: > > Thanks guys. The ideas looks theoretically sound, but for some reason the > grc > > setup I have created does not seem to like the idea of very large > interpolation > > and decimation values. It does not print out any errors, it just hangs. > > Hi Nick, > > don't use decimations/interpolations that large, the appropriate filters > are impossible to get working. > > Rather, have a look at gr_pfb_arb_resampler_ccf. You need to rationally > resample to an approximate sampling rate and let the block do the rest > by clever algorithms. > > Even if you can reach a sampling rate rationally, I usually try and > cascade it to get where I want (and I think that's how it's usually > done). > From 16e6 to 16.3676e6 is, as Ed already mentioned, 40919/40000. > GR standard tools won't give you any good anti-aliasing filters for > this, but you could go in several steps, such as > 29/20 × 17/20 × 83/100. > > However, working that out already takes longer than setting up > gr_pfb_arb_resampler_ccf, or, even easier pfb_arb_resampler_ccf.py, so > I'd recommend just using that. > > MB > > > > > > I have attached a copy of my grc setup. > > > > > > On Thu, Mar 3, 2011 at 3:39 PM, Ed Criscuolo < > [email protected]> > > wrote: > > > > > > On 3/3/11 3:04 PM, Nick Othieno wrote: > > > > Hi all, > > > > I would like to get an output of 16.3676 Ms/s. Is it then > possible to > > set a decimation values of 6.109631223? I am wondering whether > > decimation values have to be whole numbers, or whether decimation > > values > > with fraction parts are allowed. > > > > > > Decimation numbers must be integers. > > > > What you need to do is set the USRP to acquire at some value close to > > what you need, say 16 Ms/s. > > > > Then use a rational resampler with the proper numbers for > interpolation > > and decimation to get the desired rate. For instance, at 16 Ms/sec, > > set interpolation to 163676 and decimation to 160000. In this case, > both > > are exactly divisible by 4, so it could even be 40919 & 40000. > > > > @(^.^)@ Ed > > > > > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > [email protected] > > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > -- > Karlsruhe Institute of Technology (KIT) > Communications Engineering Lab (CEL) > > Dipl.-Ing. Martin Braun > Research Associate > > Kaiserstraße 12 > Building 05.01 > 76131 Karlsruhe > > Phone: +49 721 608-43790 > Fax: +49 721 608-46071 > www.cel.kit.edu > > KIT -- University of the State of Baden-Württemberg and > National Laboratory of the Helmholtz Association > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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