Re: [Discuss-gnuradio] Audio Source configuration

[Larry Van Der Jagt]

Hello:

Thanks to everyone who has replied.  It seems that audio processing has some sort of timing issues.  

When I experiment with the channelizers detailed in;

http://www.trondeau.com/examples/2014/1/23/pfb-channelizers-and-synthesizers.html

https://static.squarespace.com/static/543ae9afe4b0c3b808d72acd/543aee1fe4b09162d08633d9/543aee20e4b09162d086354d/1395272342027/fm_channelizer.grc

With the only change being setting the Mb0 clock source to default rather than as in the demo in order to get the flowgraph to run on my E310 as well as my B210,  The B210 is running on an Ubuntu 12.04 kernel 3.8.0-44-generic,  the E310 is running 3.14.2-xilinx.

I find that the code runs with minimal aU and O on the B210 connected using USB3 to an I7 machine.  

However, when I I try the exact same code Xed in to my E310 running the Dizzy Demo image with updates to allow for QTGUI and QWT to operate,   

There are very many string of approximately 30 Os  interspered with single aUs and these overflow result in completely broken unusable audio.

I am now researching what levers may be available for audio system tuning and into the possibility of switching to Jack for audio ...

As always any links or pointers are welcomed.

LVDJ

On Tue, Mar 17, 2015 at 10:30 AM, Larry Van Der Jagt <address@hidden> wrote:

Hello:

Can anyone point me to some "color" on how to work with the Audio Source.  I am working examples to transmit FM Audio and have problems with Underruns on the UHD:USRP Sink.

The examples (from files.ettus.com/tutorials/Lab_5.grc and others) I am running select Audio Source Arch:alsa and this seems to be a problem.

I have tried to replace the Device name with plughw:0,0 as suggested in the documetnation, but this does not seem to have an impact on the choice of Audio arch: alsa

If I replace the audio source with a signal source at the same sample rate all is well, but the Audio Source implements UUUUUUUUUUUU.

Using the suggestion of having the USRP expect a bit lower rate than the audio can deliver seems to implement nearly limitless delay .... the voice is received but only after a very long ... many seconds delay ... ....

At this time I am using a B210 connected via USB3 to an I7 with plenty of memory running Ubuntu 12.04 ....  I have similar issues trying to use an E310 as the transmitter ...

Any direction would be appreciated.

LVDJ