Re: [Discuss-gnuradio] where to begin

[rhubbell]

On Thu, 2008-08-07 at 17:24 -0700, Johnathan Corgan wrote:
> rhubbell wrote:
> 
> > You're saying use a soundcard since that would be the cheapest way? I
> > didn't know that was a possibility.  I'll have to explore that and look
> > through the archive. Thanks for the tip.
> 
> Just keep in mind that most audio cards have a "DC hole" due to the 20
> Hz high pass filter on their input.  If you're looking for Schumann
> resonances, these will be at 7-30 Hz, so it won't work.
> 
> You can multiply your incoming signal (in the analog domain) by a sine
> wave to move the frequencies off DC, then move it back down to baseband
> digitally with GNU Radio. (You'll need a PLL to synchronize the mixing
> frequencies.)
> 
> I think someone has already done ELF with GNU Radio a few years ago, you
> can try Google.

I will look some more than, maybe not discussed here.  

I notice the archive goes back only to Mon, 23 Jul 2001 16:40:38 -0700
but GNUradio has been around since 1998. So I'll have to look for those
older discussions too. Thanks for the guidance.