Markus and USMA friends: I have seen several posting on Defining the METRE. May be I can add in view of some discussion that I had with CALNDR-L friends and share with USMA group: �Metre New(m') is the distance represented by 1/10^5th of Arc-angle formed by 1-degree curvature on Earth (mean Radius 6371 km); and is traversed by light, in vacuum, during the time interval, 1/8508060427625436.295815TH of the Atomic Year AD 2000 or equivalent to 1/97059575.22TH of the decimal second�. Brij B. Vij <[EMAIL PROTECTED]>
>From: Markus Kuhn <[EMAIL PROTECTED]> >Reply-To: [EMAIL PROTECTED] >To: "U.S. Metric Association" <[EMAIL PROTECTED]> >Subject: [USMA:22563] Re: One Meter Date: Wed, 09 Oct 2002 10:40:46 +0100 > >"Johnathan McClure" wrote on 2002-10-09 04:37 UTC: > > Since the second can be determined to such precision I suppose it would > > be -- but how do you measure out 1 / 299 792 458 th of it to a similar > > precision? > >A well-designed caesium maser (the heart of an "atomic clock") has by >definition a frequency of exactly 9192631770 Hz. Look up in any >electronics textbook what a "phase-locked loop" is to understand how to >convert that particular frequency into any other frequency. > >Markus > >-- >Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK >Email: mkuhn at acm.org, WWW: <http://www.cl.cam.ac.uk/~mgk25/> _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com
