Re: [Discuss-gnuradio] Robert Kelley: Richard Hosking's quadrature DDS board

[Marius Hauki]

You use the DDS and a mixer to downconvert the signal to
the basesband signal that the sound card can sample. In this way you
use a simple and cheap soundcard to replace a much more expensive
high end A/D card.
The DDS could as well be a HP signal generator, but DDS
is simple to program, have a farly large freqency span, high resultion 
and is very stable.
The problems with them are that there are quanitzation noise issues as 
well as
harmonic issues.


73 de LA9EEA
Marius Hauki



smoerk wrote:

> could you explain the relationship between this DDS board an a
> soundcard?
>
> How expensive is it, if you build it by yourself?
>
> On Tue, 01 Jan 2002 17:02:06 -0800, John Gilmore wrote:
>
>
> > FYI
> >
> > Date: Mon, 31 Dec 2001 18:10:39 -0800 (PST)
> > From: Robert Kelley <address@hidden>
> > Subject: Richard Hosking's quadrature DDS board
> >
> > http://members.iinet.net.au/~richardh/Direct%20Digital%20Synthesizer%20using%20the%20AD9854%20quadrature%20DDS.htm
> >
> > This is an excellent building block for software defined radio.
> > There is nothing like it that I have been able to find.  Add a
> > pair of mixers and feed the results into a sound card and it should
> > be possible to implement a generic receiver up to 70 MHz or so.
> > A pair of phase-locked loops might be useful to clean up spurious
> > signals, however.  I have heard that the M-Audio Delta 44 is the
> > best available sound card for these purposes, short of instrument
> > grade ADC's that are out of the reach of most people.
> >
> > http://www.midiman.net/products/m-audio/delta44.php
> >
> > _______________________________________________
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> > address@hidden
> > http://mail.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
>
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