In a message dated 3/16/2007 18:32:58 Pacific Daylight Time, [EMAIL PROTECTED] writes:
Also, some high end rubidium (such as Perkin-Elmer) manufacturers are able to develope 133Rb clocks having > 450 000 hours MTBF! That'a a lot of nanoseconds! Hi Jack, we cannot expect the units to work that long. Hard Disks have >50K MTBF, and fail all the time in much less time depending on how they are used etc. MTBF is a mean, meaning in the real world the Perkin Elmer unit could fail in the first 10 minutes, just that the statistics for that to happen have pretty low probability. When they calculate MTBF, they probably don't take into account external effects such as AC voltage spikes due to janitors pluggin-in vacuum's or due to lightning etc, earthquakes, user obuse, water damage, movement, effects of UV light on plastik parts such as cables, Tin Whisker shorts, electrolytic capacitor dryout, mouse damage, etc. I think it's pretty useless to say a piece of equipment has a MTBF of over 50 years. Then again that's only an opinion... bye, Said ************************************** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
