Console full of "aUaUaU" messages, distorted audio

[Richard Klingler]

After I tried my Funcube Dongle Pro+ with DSP Radio and SdrDx on OSX I found this nice programmm...and as it was available as a package for Ubuntu, even better (o;

During reception of FM test broadcast with 75kHz modulation I see from time to time loads of "aUaUaU" console messages
and during that time the audio is distorted like mad....like it would print messages to audio out as well (o;

When I switch from WFM to Narrow FM and back again....the audio is continously distored for several seconds...
until the log messages disappear...


So no clue where those messages are coming from and what they mean...and why they distort the audio heavily...



Gqrx: gqrx-sdr 2.2.0.74.d97bd7-2
OS: ubuntu 14.04 LTS, Linux 3.13.0-32-generic
FCP+ FW 20.03

[Alexandru Csete]

On Tue, Aug 5, 2014 at 3:49 PM, Richard Klingler
<richard....@gmail.com> wrote:
> After I tried my Funcube Dongle Pro+ with DSP Radio and SdrDx on OSX I found
> this nice programmm...and as it was available as a package for Ubuntu, even
> better (o;
>
> During reception of FM test broadcast with 75kHz modulation I see from time
> to time loads of "aUaUaU" console messages
> and during that time the audio is distorted like mad....like it would print
> messages to audio out as well (o;
>
> When I switch from WFM to Narrow FM and back again....the audio is
> continously distored for several seconds...
> until the log messages disappear...
>
>
> So no clue where those messages are coming from and what they mean...and why
> they distort the audio heavily...

aU comes from gnuradio (the library on which gqrx is built on) and
means audio underrun. In English: Samples are not sent fast enough to
or from the soundcard. In this case I suspect the problem is the the
FCD Pro+ input since it also acts as a sound card.

There are many problems running the FCD Pro+ on linux and whether it
works depends greatly on the USB host controller, see
https://github.com/csete/gqrx/issues/91
I don't have much experience with Ubuntu 14.04 and the newer kernel
may also have influence on how well it works.

In your case it could also be high CPU load.

Alex