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:[email protected]]
*Sent:* Tuesday, 22 May 2018 11:19 AM
*To:* Yeo Jin Kuang Alvin (IA); [email protected]
*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:[email protected]] *On
Behalf Of *Marcus D. Leech
*Sent:* Tuesday, 22 May 2018 11:02 AM
*To:* [email protected] <mailto:[email protected]>
*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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