[time-nuts] Looking for Wavecrest Visi

SAIDJACK at aol.com SAIDJACK at aol.com
Sun Apr 8 15:42:15 EDT 2007


 
In a message dated 4/8/2007 04:02:38 Pacific Daylight Time,  
bruce.griffiths at xtra.co.nz 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.


More information about the time-nuts mailing list