Hi Said,
That equation looks similar in form to the specs for any counter. What
are the comparable equations for the 53132A or the 5370(A or B)?
Ed
On 3/17/2013 10:41 AM, Said Jackson wrote:
Volker,
The error I have seen was in the high xE-011's to the low xE-010's. the only
way around it was to turn on relative measurements, which then subtracted out
this error. That error makes the unit almost useless to me.
The factory told me as long as it is within specs they will ship it after cal
and not bother trying to improve this.
The "acceptable" specs are pretty crappy in tim-nuts terms: +/-350pico *
frequency with a 1s gate time. Thats straight from the user manual and assuming no
reference error. From the manual:
Frequency Accuracy:
< ± ((100ps typ [350 ps max])/Gate + Timebase Error ) x Frequency
That equates to up to +/-3.5E-010 if my math is right!
Not so impressive. I can confirm Ricks comment about HP 53132A units not
showing that type of error.
Not knowing how big the error is without another non-SRS counter to compare to,
and if it may actually be bigger than spec is a problem. I don't remember if it
shows up when feeding the counter its own reference.
Bye
Said
Sent From iPhone
On Mar 16, 2013, at 16:06, Volker Esper <ail...@t-online.de> wrote:
What "small error" are we speaking about? The statement that SRS users have to
tolerates a small error while HP users don't seems a little to general to me. IMHO we
might be a bit more precise. Anyone who's already done an error analysis for - say - a
10MHz count and a comparison of the counters?
In real life every type of equipment has it's domain, where it has it's
specific advantage. Could it be, that's the case for these counters, too?
Cheers
Volker
Am 16.03.2013 19:57, schrieb Rick Karlquist:
1) I paid quite a bit of money and I had it "calibrated" and fixed by
SRS,
and it still exhibits a significant frequency offset with a "perfect"
reference and "perfect" DUT!!!
SRS says a small frequency error is "normal", well that prevents me from
using the unit as a frequency counter, for me it's only useful as a
relative
display frequency counter. HP doesn't have such a frequency error, so no
worries there.
I worked with the guy who designed the HP53132A. He would
never tolerate as "normal" a so-called small error. The term
"frequency counter" brings to mind something that digitally counts
zero crossings and should never have an error. First of all, even
if that is all you do, it is still possible to screw it up.
Secondly, "counters" have relied on analog interpolation even going
back to the HP524 circa 1950. There is no theoretical basis of having zero
error in this case, but the idea is that you display the number of
digits that are commensurate with the worst case accuracy of your
interpolator. Again, my colleague who designed the interpolator
did very high quality work. I am pleased to learn that our stuff
is better than the stuff from the company up the road.
Rick Karlquist N6RK
HP Santa Clara Division 1979-1998
(still working for Agilent!)
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
