Re: [Discuss-gnuradio] Sample audio from my FM stereo receiver

[Marcus D. Leech]

On 12/03/12 10:08 PM, Andrew Davis wrote:
> Doesn't sound as good to me, maybe it's just a bad sample. I for some
> reason ( I know the math tells me otherwise ) I find it sounds better
> the faster I sample, like 500M. I feel like it has something to do
> with more exact following of the FM signal curve or something.
>
>   
I had the bass turned up, which matches my speakers well, but now that
I'm listening to the
  "Baba O'Reilly" sample on my headphones, it's quite a bit too bassy.


> So how exactly does the software FM Demod work ( crossing detection )?
> And why can my $5 toy FM radio sound so much cleaner?
>
>   
It's a quadrature demodulator using ATAN2--not a simple crossing
detector. It should be quite high
  fidelity.

Some of these "listening tests" are notoriously subjective as well, and
the source material varies wildly
  in quality.

The other thing is this receiver doesn't do any deemphasis processing,
choosing instead to have a 3-band
  equalizer with settable gains that allow you to tweak the audio
spectrum of the output a bit.  Some keener
  could make it more fine-grained to tune the resulting sound to suit
personal preferences/room/etc.






-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org