Re: [Discuss-gnuradio] System overrun after short time

[Josh Blum]

On 07/23/2012 03:08 AM, Luong Tan Phong wrote:
> Hi Lists,
> 
> I wrote a program in C + + use gnuradio library to demodulate some signals. 
> The
> program works well with the low data rate signal (below 20
> Ksymbols/s). With higher
> data rate signal: 200 Ksymbols/s, the program works well for a few minutes
> then the console window will appear the letters 'O' continuously and data
> after demodulation was wrong. With 1 Msymbols/s signal, the system can
> operate well over 1 minute.
> 
> Could you help me to solve the problem, please?
> 

It sounds like you found the tripping point where the rate of data
flowing into the buffers exceeds the rate of data being removed.

http://files.ettus.com/uhd_docs/manual/html/general.html#overflow-underflow-notes

I admit, that is a rather low rate. Perhaps you have a filter with an
unexpectedly large number of taps? Or you max consider benchmarking the
performance of your demodulator code, or try to isolate which processing
block is slow, etc

-josh