Article on "Antialiasing filteres and multirate systems"

Hello all,

Following a small research I conducted after posting my question about
antialiasing of ADC samples to sci.electronics.design, I wrote a small
and simple article to explain to myself, once and for all, the deal
about analog & digital antialias filters, multirate systems and how
these are connected.

The article is here:
http://eli.thegreenplace.net/2006/05/10/antialiasing-filteres-and-multirate-systems/

I hope it will be useful for others. If you find mistakes, inaccuracies
or useful things to add, do let me know, I will do my best to beat it
into shape.

Regards,
Eli