Hi Alvin: You need to widen the transition bandwidth, not reduce it! Going from 1000 to 150 Hz will greatly increase the complexity of the filter. Try 5000 Hz to see if you get better performance.
Kevin Sent from my iPad > On May 21, 2018, at 20:14, Yeo Jin Kuang Alvin (IA) <yjink...@dso.org.sg> > wrote: > > Hi Marcus, > > Thank you for the quick reply! > > Is there any block in GRC that works with the FPGA in the USRP B210? And I > have tried lowering the transition width from 1000 to ~150 but I still see > overflow, does this means that the only solution to it is to get a faster > computer? > > Thank you in advanced! > > From: Discuss-gnuradio > [mailto:discuss-gnuradio-bounces+yjinkuan=dso.org...@gnu.org] On Behalf Of > Marcus D. Leech > Sent: Tuesday, 22 May 2018 11:02 AM > To: discuss-gnuradio@gnu.org > Subject: Re: [Discuss-gnuradio] GNURadio Companion LPF > > On 05/21/2018 10:54 PM, Yeo Jin Kuang Alvin (IA) wrote: > Hi all, > > Apparently, I tried connecting the USRP Source to a Low Pass Filter and to a > File Sink, I get overflows “OOOOOO”. However, when I removed the LPF, there > is no overflow. The question is, why is this happening? Is the Low Pass > Filter in GRC done in the FPGA or in the computer itself? I am using USRP > B210 and my sampling rate is 6MHz. > > Is there a solution to this? > > Thank you in advanced! > > 'O' are caused by the computer not "keeping up". Gnu Radio is a > software-defined-radio framework, and all the blocks execute on the PC host. > > It is typically the case that new users make low-pass filters with very > "aggressive" transition bandwidths, which leads to a very expensive-to-compute > filter. Try relaxing the transition bandwidth. > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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