added a couple paragraphs for people who don't know what anti-alias filters are.
added a couple paragraphs for people who don't know what anti-alias filters
are.

olsonse/comedilib,olsonse/comedilib,Linux-Comedi/comedilib,Linux-Comedi/comedilib,olsonse/comedilib,Linux-Comedi/comedilib,Linux-Comedi/comedilib,olsonse/comedilib,olsonse/comedilib,olsonse/comedilib,Linux-Comedi/comedilib,Linux-Comedi/comedilib