[time-nuts] Agilent appnote

Joseph Gray jgray at zianet.com
Mon Jul 25 12:42:05 EDT 2005


> That is two methods yes (you need to distinguish between phase-delay and
> group-delay). However, considering that he was reading AP200-3 the text 
> giving
> the reference is:
>
> +/- Systematic Error

Magnus, your psychic ability is amazing :-) Yes, I was reading AP200-3. I'm 
surprised that I can't find AP174-10 at Agilent, though.

Thanks to everyone for the helpful suggestions. I had actually done a simple 
measurement of a cable with my 5370A. I saw this method mentioned on John 
Ackerman's site. The results I came up with were a bit longer than the 
actual cable. I wasn't sure if this was due to the BNC connectors and tee 
adapter, or some error in my measurement.

Here is what I got with the average of 100 measurements: Mean = 19.197 nS

I calculated the mean value times C (299,792,458 m/S) and then by the
velocity factor (Beldin RG-58AU is .66, right?). This comes out to 12.47 ft.
The coax I was using is 12 ft long.

As for the phantom appnote, I would still like to see a copy. It may provide 
further insight into the process.





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