USRP underrun problems

GNU Radio
1

Hello, I trying to implement DVB-H Standar on GNU Radio and USRP.

In software, all run ok, but now I’m doing the first test with USRP and
I
have a problem that I have no idea how fix it. When I try to send with a
Flex 900, freq=850M, fft-Lenth=2048, occupied-tones=1512 the program
print
UuUuUuUu, USRP underrun ¿How I fix it?

Cheers

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2

On 06/04/2010 03:47 AM, Chris_Spain wrote:

Hello, I trying to implement DVB-H Standar on GNU Radio and USRP.

In software, all run ok, but now I’m doing the first test with USRP and I
have a problem that I have no idea how fix it. When I try to send with a
Flex 900, freq=850M, fft-Lenth=2048, occupied-tones=1512 the program print
UuUuUuUu, USRP underrun ¿How I fix it?

Cheers

You should make sure you have realtime scheduling enabled. If you do,
and still get underruns a lot of underruns, then your computer is not
fast enough to run your program in real time.

Matt

3

Hello Matt thank you for your answer, I’m sure that realtime scheduling
is
enabled because my program don’t print the following warning:

r = gr.enable_realtime_scheduling()
if r != gr.RT_OK:
print “Warning: failed to enable realtime scheduling”

So, My computer is not fast enough to run my program en real time? How
can I
fix it? I Have a Pentium IV 3.0 Ghz HT

Thanks a lot.

4

On Sat, Jun 05, 2010 at 11:24:15AM +0100, Christian Pérez wrote:

Hello Matt thank you for your answer, I’m sure that realtime scheduling is
enabled because my program don’t print the following warning:

r = gr.enable_realtime_scheduling()
if r != gr.RT_OK:
print “Warning: failed to enable realtime scheduling”

So, My computer is not fast enough to run my program en real time? How can I
fix it? I Have a Pentium IV 3.0 Ghz HT

Not to be glib, but signal processing is one of the more CPU intensive
operations that you can attempt. Consider buying a much more recent
computer. Perhaps something like a dual or quad core i7?

Eric