In a message dated 4/8/2007 04:02:38 Pacific Daylight Time, [EMAIL PROTECTED] writes:
The Wavecrest instrument only has a single shot resolution of 25ps not as you claim 800fs (this is only achieved after averaging) The above counters can only be compared for this purpose if their single shot resolution and linearity are known. Hi Bruce, again, I did say in my original post that my math only works if their noise is Gaussian, and that I did not know if it was. Also, please note that they do claim 25ps Accuracy , and 800 femtoseconds Hardware resolution, not the other way around. They claim +-25ps accuracy with 3-sigma confidence. The user manuals are available on the Wavecrest website. There is no mention in their documents that averaging is needed to make use of their 800 Femtoseconds hardware resolution; quite the contrary in some older white-paper documents they show how they achieve this single-shot resolution (when looking inside one of these units it's quite amazing technology). Keep in mind that these instruments are on a totally different level than the 53132A or SR-620: these units cost anywhere from $50,000 to $90,000 new. BTW: the only point I was trying to make is that you sometimes can get these things for <$500 and they are a lot better than the above mentioned instruments for time-interval measurements. Bye, Said ************************************** See what's free at http://www.aol.com. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
