On Mon, Mar 22, 2010 at 01:49, Charles Brain <chbr...@btinternet.com> wrote:
> I have tried the fractional interpolator and it just sucks too many CPU > cycles. There is one more thing you can try--use the polyphase resampler. This is a new block by Tom Rondeau based on the Harris book. It hasn't gotten a lot of use yet, but it is working so far and is very efficient. gr.pfb_arb_resampler_ccf(resample_rate, taps, size) 'resample_rate' is your desired interpolation rate 'taps' is the vector of FIR taps to use as the interpolation filter 'size' is the number of phases to use in resampler (default=32) You can use gr.firdes.* to design a filter to create 'taps'; but the sample rates to use require special calculation. See: http://gnuradio.org/redmine/repositories/entry/gnuradio/gnuradio-examples/python/pfb/interpolate.py ...for an example using both the polyphase integral interpolator and the polyphase arbitrary resampler. In your case, if I recall correctly, your final output filter is a root-raised-cosine filter. So you'd use the arbitrary resampler to upsample to your final output sample rate, and use the RRC tap generator to create the taps for it. Johnathan _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
