Hi Jason, so talking about the GNU Radio rational resampler: > Under the hood, is GNURadio basically creating a FIR > decimator? Yeah! Multirate processing! So what happens in the block that's called "rational resampler" in GRC is that if you leave "taps" empty, the Python block [1] designs a FIR that suppresses images (on interpolation) or aliases (on decimation), whatever is harder (ie. anti-image filter if interp>decim, anti-alias otherwise). Basically, a "little less than Nyquist max" low pass is built. These taps are then used in the C++ rational_resampler_base_XXX, which does a bit of polyphase magic. Which, when interp=1, leaves you with a f_nyquist*0.8/decim LPF with decim decimation.
Cheers, Marcus [1] gr-filter/python/filter/rational_resampler.py On 26.10.2015 13:27, Jason Matusiak wrote: > I think I am overthinking something with the rational resampler. I am > working on an RFNoC block to incorporate a working gnuradio script we > have, and am somehow being silly about the rational resampler. > > I am decimating by 4 (and not interpolating at all), to reduce the > sample rate by 4. Under the hood, is GNURadio basically creating a FIR > decimator? Is it that simple, or am I missing some other pieces? > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
