Re: [Discuss-gnuradio] audio quadrature input

[Eric Blossom]

On Thu, Oct 21, 2004 at 03:32:05PM -0400, cswiger wrote:
> Gang - Is there some code that can read I/Q signals from the audio
> line-in? There's support for the SDR-1000 but that looks like
> parallel port control stuff. What do you use the process the SDR-1K
> signals? It's not leaping out at me.

Use audio.source.  It produces either one or two outputs.

from gnuradio import gr
from gnuradio import audio


  src = audio.source (sample_rate)
  f2c = gr.float_to_complex ()
  
  next_block = ...

  ...

  fg.connect ((src, 0), (f2c, 0))
  fg.connect ((src, 1), (f2c, 1))

  fg.connect (f2c, next_block)


> I've just finished a commutating mixer (formerly 'tayloe') detector
> and suprisingly it works ;) with the SDRadio software of I2PHD.
> Of course it's limited to +-20Khz with a hole in the middle.
> 
> Also, I was talking with John Gilmore about audio quality - is
> a certain amount of clicking and warbling a part of gnuradio or just
> my sound card? It's a mobo integrated sound system, might be
> worth investing in a real sound card if that would help clean it up.

Shouldn't be any clicking or warbling.  If you're using the ALSA
drivers (probably the right answer), we're using the OSS emulation on
top of ALSA (probably not the right answer).  It would be great if
someone (Chuck??) would write the native gr-audio-alsa blocks.

Eric