> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
Behalf
> Of Rich
> Sent: 05 August 2008 14:37
> > Rich wrote:
> >> I have not followed this thread but the title caught my eye.  One
very
> >> important thing to remember when driving the input to  an A/D is
that
> >> the output impedance of the driver should be kept as low as
possible
> >> in order to avoid aliasing and conversion error.



> From: "Olin Lathrop" <olin_piclist@embedinc.com>
> >
> > Conversion error, yes.  But A/D source voltage impedence has nothing
to
> > do with aliasing.


> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
Behalf
> Of Rich
> 
> I disagree!  Think it through.  What happens if the source impedance
is to
> high and cannot source the required current or even sinks current from
the
> converter?  Analog Devices has some good articles on this.  True, they
are
> older articles, but they can still apply depending on the choice of
> devices used.

If the source impedance is too high, then it simply reduces the accuracy
of the converted measurement.  It does not cause aliasing which is an
artefact of sampling below the Nyquist frequency.

Regards

Mike

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