> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Poul-Henning Kamp > Sent: Friday, January 18, 2008 3:58 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Slightly OT: inexpensive USB > analog-digitalconverter? > > > The measurement errors are static and can be calibrated out, > the major one I found is stray magnetic fields. >
We use those and sensitivity to stray fields is indeed the most significant beef I have with them (low bandwidth being another, and drift being the icing on the cake :-) I have not looked at their complete line, and maybe I should, but those we use have a nominal output for zero current that is not zero volts, so they require a differentiual amplifier and an additional voltage reference which brings its own set of problem and complexity. However, it's easy to get 1500VAC isolation (as I am required in the application where I use them) and DC coupling. Bottom line, if you can live with the moderate precision they offer off-the-shelf, they are great, but don't try to improve on it or you'll hit all sorts of brick walls. Didier KO4BB No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.2/1223 - Release Date: 1/13/2008 8:23 PM _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
