[time-nuts] Glitches in data

[John Miles]

That doesn't look like a GPIB interface bug to me.  Those usually involve
duplicating or dropping data rather than arbitrarily turning multiple ASCII
digits into others.  Given the nature of those outliers I'd suspect a
problem with the calculations made by the counter itself.

Although: the later GPIB-USB and GPIB-LAN firmware is a pretty important
update for some instruments, due to a change made in the way the bus pullups
are used.  If you are using either of these adapters, you should make sure
you have the latest update installed.

-- john, KE5FX


> Hi
>
> I've had the same thing happening with a Prologix Ethernet setup until
> firmware 1.5.1.0.
> -Henry
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Hal Murray
> Sent: Wednesday, July 08, 2009 7:17 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Glitches in data
>
> I've got an HP 5334B collecting data via a Prologix USB setup.  It's
> been
> running for months.
>
> Mostly, it's doing what I expect.  But then I got 2 glitches in the last
> two
> days.
>
> Here is a graph:
>   http://www.megapathdsl.net/~hmurray/time-nuts/Drift-ocxo3mhz-d.gif
>
> Here is the raw data:
>
> It's the 2.999... column.  The second column is seconds in the day day.
> They
> are 5 minutes apart.
>
> 55019 65824.624 F +2.9999996881E+06 F +3.2768070130E+04
> 55019 66124.710 F +2.9999996881E+06 F +3.2768070725E+04
> 55019 66424.796 F +2.9999996880E+06 F +3.2768071164E+04
> 55019 66724.882 F +2.9999997045E+06 F +3.2768071592E+04 <==
> 55019 67024.968 F +2.9999996878E+06 F +3.2768072178E+04
> 55019 67325.054 F +2.9999996878E+06 F +3.2768072586E+04
> 55019 67624.140 F +2.9999996880E+06 F +3.2768073011E+04
> 55019 67924.226 F +2.9999996881E+06 F +3.2768073466E+04
>
> 55020 61924.265 F +2.9999996883E+06 F +3.2768068930E+04
> 55020 62224.351 F +2.9999996884E+06 F +3.2768069393E+04
> 55020 62524.437 F +2.9999996882E+06 F +3.2768069919E+04
> 55020 62824.523 F +2.9999997030E+06 F +3.2768070314E+04  <==
> 55020 63124.609 F +2.9999996885E+06 F +3.2768070508E+04
> 55020 63424.695 F +2.9999996885E+06 F +3.2768070907E+04
> 55020 63724.781 F +2.9999996878E+06 F +3.2768071254E+04
> 55020 64024.867 F +2.9999996879E+06 F +3.2768071523E+04
>
>
> Does anybody have any suggestions for what is causing things like this?
> Or a
> checklist of things I should consider?
>
> Everything is plugged into the same outlet.  The OCXO is powered by a
> wall
> wart.
>
> I wasn't near it at either time.
>
> My UPS didn't see any power glitches at either time.  (They are not
> running
> off the UPS.  For this, I'm just using it to monitor power.)
>
>
>
>