Tom,

>This doesn't sound like a performance issue.
I absolutely agree.

>I think you're probably looking at a sample rate mismatch somewhere.
 If it were the case. Don´t you think that FM transmitter by itself and FM
receiver by itself shouldn´t work neither?
The point is that both of them when running alone work. That is the fact I
do not understand.

Regards,
Jorge.



On 2 October 2010 17:03, Tom Rondeau <[email protected]> wrote:

> On Thu, Sep 30, 2010 at 5:52 AM, Jorge Miguel <[email protected]> wrote:
> > Hi !
> >
> > Eric, thanks for your advise. Some results here.
> >
> > I set my computer into "performance mode". At first sight nothing
> improves.
> >
> > With the example usrp2_fft.py I can low the decimation to 5 and the
> > application works ok.
> >
> > As I said the FM modulator works ok by itself. The FM demodulator also
> works
> > ok by itself. The problem is when I run both in the same flowgraph. I
> think
> > it is not a problem of performance since my CPUs are not very work-loaded
> > when my application is running.
> >
> > My problem is that changes, in the FM modulator, which I think they would
> > increase performance (like increasing my 13 interpolation in the USRP and
> > decreasing my software interpolation) make my receiver chain non-working
> > (SSS messages) although the transmitter outputs a perfect FM signal.
> >
> > I do not understand these mesages since my CPUs are less than 15-20%
> used.
> > However something is stopping the received data because I got a lot of
> > dropped frames in my rx Ethernet interface (saw with ifconfig). I tried
> to
> > increase the RX Ethernet buffer (sysctl -w net.core.rmem_max=XXXXX) but
> it
> > didn't work. I also tried to set in my generated code the USRP source
> > instance before the USRP sink but it didn't work neither.
> >
> > Could be any reason why by decreasing software computation (and Ethernet
> > traffic as well) in the transmitter path affects the performance of the
> RX
> > path?
> >
> > Many thanks,
> > Jorge.
>
> This doesn't sound like a performance issue. I think you're probably
> looking at a sample rate mismatch somewhere.
>
> Tom
>
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