Hi all, What are the disadvantage of having overflows and underflows? I am working on radar projects which is in real-time, will these underflows and overflows affect my results? Sorry I am still trying to learn all these.
Thank you in advanced! From: Marcus D. Leech [mailto:mle...@ripnet.com] Sent: Tuesday, 22 May 2018 11:32 AM To: Yeo Jin Kuang Alvin (IA); discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] GNURadio Companion LPF On 05/21/2018 11:28 PM, Yeo Jin Kuang Alvin (IA) wrote: Hi all, Thank you! I've noticed my mistake. Now I've tried both 5000 and 100e3, instead of overflowing "O", I see lots of "L" late packets. Thank you in advanced! 'L' is from TX side of things. It's a special variant of 'U', where the transmission is time-tagged, and the device time is already past that point when the time-tagged packet arrives. From: Marcus D. Leech [mailto:mle...@ripnet.com] Sent: Tuesday, 22 May 2018 11:19 AM To: Yeo Jin Kuang Alvin (IA); discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org> Subject: Re: [Discuss-gnuradio] GNURadio Companion LPF On 05/21/2018 11:14 PM, Yeo Jin Kuang Alvin (IA) 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? There are no FPGA-for-B210 blocks in Gnu Radio. That's not how Gnu Radio works. RFNoC is an exception, but B210 is not an RFNoC-capable radio. Narrowing the transition width (as a fraction of sample-rate) is precisely how you end up with really-long, hard-to-compute, filters. Try a transition width of 100e3, and see how that does. That's a roughly 2% fractional bandwidth. Which, in the analog world, would be a pretty "tight" filter. 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<mailto: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.
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