Re: [Discuss-gnuradio] why quadrature samples?

[Mark Smith]

Allow me to throw my request into the hat for more technical detail
on this subject, or at the very least, a good reference on where we
can read up on it ourselves.  This is a new concept to me that I'd
love to have more detail on.

Thanks!  :)

-Mark

On Tue, Jan 21, 2003 at 06:16:56PM -0800, Chris Albertson wrote:
> 
> Someone who knows more please add to this....
> 
> Practically, I think what you gain is two independent samples
> of the signal.  In theory this will boost your S/N by a factor
> of 1.41 or sqrt(2).  
> 
> Matmatically you are sampling the data as complex numbers.
> complex FFTs are Matmatically "nicer" in that they are
> symetric and so forth.  But what do engineers care bout
> "matmatically nicer"?
> 
> 
> --- Stephan Olbrich <address@hidden> wrote:
> > Hi,
> > 
> > > Going back to my soundcard suggestion, you could buy a 96ks/s
> > stereo soundcard
> > > for less than $100 these days.  Take your input signal, mix it
> > (multiply) by a
> > > 48 kHz sine and cosine wave, lowpass filter those 2 outputs, and
> > feed to the
> > > soundcard stereo inputs.  You'll have sampled the spectrum from 0
> > to 96kHz at 24
> > > bits per sample.
> > Can someone give me a hint what's the point in mixing with a sine and
> > cosine and sample both signals? 
> > 
> > Stephan
> > 
> > 
> > 
> > 
> > _______________________________________________
> > Discuss-gnuradio mailing list
> > address@hidden
> > http://mail.gnu.org/mailman/listinfo/discuss-gnuradio
> 
> 
> =====
> Chris Albertson
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-- 
Mark Smith - finger address@hidden for GPG v1.0.1 public key

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