[time-nuts] HP 5065A control

jim_johnson at agilent.com jim_johnson at agilent.com
Wed Nov 3 19:28:37 EST 2004

Hi Bill,

   I checked with one of my "gurus", with email
out to another, and what was suggested is that
there is a chance that the standard could "lock
to the wrong line", a reference to the operation
of the internal physics package.  This might be
what you're seeing with the unstable second harmonic
reading.  Also, a rapid change of the "C-field"
adjustment, as it's called, can result in a very long
relaxation time due to the three layers of magnetic
shielding in the unit.  Trying to servo that could
be quite challenging since it make take "days" to
recover to full specification from a rapid change
in the mag field setting.  That would result in a
very long-time-constant servo loop.  If I get more
information on this, I'll post it.

Jim Johnson
Agilent Laboratories
Palo Alto, CA
jim_johnson at agilent.com

>-----Original Message-----
>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
>Behalf Of Bill Hawkins
>Sent: Wednesday, November 03, 2004 9:47 AM
>To: Discussion of precise time and frequency measurement
>Subject: [time-nuts] HP 5065A control
>Recently installed a 5065 in a steel rack cabinet, and needed
>to move the magnetic field adjustment from 320 to 400 or so.
>When I changed the field, the 2nd harmonic meter reading went
>unstable, showing random values between 10 and 50. This would
>settle down to 12 with an occasional tic upwards. Is that
>normal behavior?
>Given the sensitivity to the field adjustment, it seems to me
>that a servo capable of swinging the field a few minor divisions
>could be built with a long time constant. This should allow the
>5065 to be brought exactly to GPS time from an HP Z3801 receiver.
>Has anybody tried this? Anybody know why it wouldn't work?
>Bill Hawkins
>time-nuts mailing list
>time-nuts at febo.com

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