Re: [Discuss-gnuradio] Re: Some questions about audio output and under-runs on a custom block....

[Eric Blossom]

On Wed, Sep 09, 2009 at 10:41:49AM +1000, Steve Glass wrote:
> Hi Eric,
> 
> Thanks for the range information ... it seems right but I wanted to be sure.
> 
> Is there a rate limiting block upstream of custom_block_ff, such as a
> > usrp or usrp2?
> >
> There is indeed, either a USRP or a file with a throttle at the appropriate
> rate for the block's input.

You almost never want to use a gr_throttle block.  It was primarily
created to test some GUI code.

I suspect that if you remove the gr_throttle that the code will work
fine.  In the case of the USRP, you've got the "two clock problem".
That is, there are two clocks in the system (usrp and audio) and they
are not synchronized and are running at different rates.

If you are using portaudio, you might try specifying False for the
third parameter to the audio_source constructor.  (I'm not sure what
kind of shape the portaudio source/sink is in.)

Eric