Re: [Discuss-gnuradio] gnuradio/usrp (almost) working / IIR filter design code

[Eric Blossom]

On Thu, Jun 02, 2005 at 10:19:23PM +0200, Jens Elsner wrote:
> Hello,
> 
> after some hours of fighting with wxpython and other dependencies 
> gnuradio/usrp works - almost. 
> 
> No audio output so far:
> 
> ice:/home/ice/gnuradio/gr-build/gnuradio-examples/python/audio# 
> ./mono_tone.py -d /dev/dsp
> ALSA lib pcm.c:2068:(snd_pcm_open_noupdate) Unknown PCM /dev/dsp
> audio_alsa_sink[/dev/dsp]: No such file or directory
> Traceback (most recent call last):
> ...
> 
> Hints would be greatly appreciated.

Don't add -d /dev/dsp to the command line.  /dev/dsp is an OSS device
file.  The ALSA devices have names such as hw:0,0 or plughw:0,0

> I just browsed the "suggested projects" page - is there any demand for
> python IIR filter design code? I'd like to give it a shot, but what are
> the applications? I was told that IIR filters are almost dead in the digital 
> age because of non-linear phase.

They're not dead.  And yes, IIR filter design code would be useful.
There are at least two existing packages we might want to use:
libfilth and part of scipy.

The problem I had with scipy was that it had a huge list of
dependenicies.  It did however have a complete library of functions
for designing all kinds of filters.

Eric