Re: [Discuss-gnuradio] gnu radio with a soundcard

[Theo Verelst]

John R. wrote:
> Mathew George wrote:
>
> > Hi all,
> >
> > Can someone explain how we may build a FM/SW receiver using A/D D/A 
> > converter in a sound card and minimal additional hardware? Somewhere I 
> > have read that this is possible, in principle, but could not yet 
> > gather info suitable for a novice.
>
>
> I am attempting the same general thing.  I am pretty sure you will need 
> a radio receiver that has an IF output.  My AOR 8200 has a discriminator 
> output which I think is something different.  In theory it has an IF 
> output also but have not seen anything showing how to use it.
>
> John

Well, I´m sure you´ll have to decide on what you want, because great FM
sound by feeding something through a sound card isn´t sounding realistic.

You can not get more informations per second generally from a
soundcards´ output than you put in the input, roughly...

So you could detect and such signals which could be sampled from some
receiver if the bandwith would be limited to what a soundcard can
digitize, so without aliasing that would be 20kHz or maybe higher. The
intermedeate frequency in radios would be much higher, more megaherzes

A discriminator output may be applicable, but the processing of such a
signal into a FM decoded signal may not be what sr is usually used for.

In most cases the much higher sampling rate of the hardware device for
sr is needed to get a demodulatable signal I think, as well the
soundcard input may have not right impedances compared with radio boards.

Very low frequency signals could be AD converted by soundcard, or a
signal with small bandwidth mixed into the audio band.

Theo