[USRP-users] Fwd: Removing DC offset on USRP B200
Marcus D. Leech
mleech at ripnet.com
Tue Oct 31 13:19:59 EDT 2017
On 10/31/2017 01:15 PM, Oliver Wayne wrote:
> Another thought I had -- because I don't anticipate my waveform
> changing much, is there a way to pre-record my waveform and transmit
> it continuously, which if I understand the problem correctly would
> avoid the underruns?
Sure, just record it in a file-sink, and then play it back from a
> On Mon, Oct 30, 2017 at 3:28 PM, Oliver Wayne <olivergwayne at gmail.com
> <mailto:olivergwayne at gmail.com>> wrote:
> Hi Marcus,
> I switched to performance mode and got the same results. I'm
> running LDXE on this computer, so I changed it by editing
> /etc/init.d/cpufrequtils and setting GOVERNOR="performance", then
> using sysv-rc-conf to deactivate on-demand.
> On Mon, Oct 30, 2017 at 3:01 PM, Marcus D. Leech
> <mleech at ripnet.com <mailto:mleech at ripnet.com>> wrote:
> On 10/30/2017 02:54 PM, Oliver Wayne wrote:
>> When I run perf top, I get libuhd.so.3.11 and libc-2.23.so
>> <http://libc-2.23.so> taking up about 15% and 21%
>> respectively, rising over time. This is at 10Msps. any
>> thoughts? I've tried a few other things like setting
>> otw_format=sc12 and setting the frame size higher, but I
>> haven't had any success.
> Could you try running your CPU in "performance" mode, rather
> than the power-saving 1.6GHz mode that it is apparently
> running at?
>> On Tue, Oct 24, 2017 at 3:42 PM, <mleech at ripnet.com
>> <mailto:mleech at ripnet.com>> wrote:
>> You could perhaps do a "perf top" and see what's
>> consuming time.
>> The Gnu Radio signal source blocks are not screamingly
>> efficient, so it may be that they just aren't keeping up,
>> although at 4Msps, you wouldn't expect them to be too
>> On 2017-10-24 15:12, Oliver Wayne via USRP-users wrote:
>>> Apologies for not forwarding to the full list. I'm
>>> attempting to run the attached flowgraph with the
>>> following hardware, but getting underflows.
>>> I have 8 GB of RAM, so don't think that's a problem.
>>> Running lspci | grep -i usb, I get the following output
>>> 00:1a.0 USB controller: Intel Corporation 6 Series/C200
>>> Series Chipset Family USB Enhanced Host Controller #2
>>> (rev 04)
>>> 00:1d.0 USB controller: Intel Corporation 6 Series/C200
>>> Series Chipset Family USB Enhanced Host Controller #1
>>> (rev 04)
>>> I've attached a copy of cpuinfo.
>>> USRP-users mailing list
>>> USRP-users at lists.ettus.com
>>> <mailto:USRP-users at lists.ettus.com>
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the USRP-users