[Test-Equipment] Quartz Oscillator Adventures

[Shaun Merrigan]

I've been having a great time over the last month or so
learning about the characteristics of precision quartz standards
(HP-105B, Manson RD-180A, Austron 2010B) and frequency metrology
in general.

This all started with acquiring an HP-Z3801A GPS disciplined frequency
standard. I de-mothballed a Manson RD-180A, downloaded all the HP App Notes
(about frequency, time, and the measurement of same) I could find, and
started making phase comparisons.

I am using an HP1707 scope, triggered by the standard, for the phase
comparisons.
The oscillators have been running continuously for up to 4 weeks now.
Although I
don't have a method of taking automated equal-interval measurements as yet
(for Allan
variance calculations), I have measured the offset of the RD-180A over
several
24hr periods (it has been running continuously for the longest tine). It
turns out
to have an average frequency offset of 4x10E-10 over 24 hours. The HP105 is
settling
down after a about a week of continuous operation; I'll be interested to see
what
it does after several weeks.

My next step is to develop the ability to automate phase measurements in
order to
characterize the oscillators using Allan variance (or a derivative). I would
also
like to do this for my GPS standard by measuring the EFC voltage. As well as
a 10Mhz
GPS disciplined standard, I have a GPS derived 1 PPS available. So I could
go the
phase comparison (phase meter?) route or the decade/divide-time interval
route. Any
suggestions? Comments?

Of course, now I feel a pressing need for a LORAN based comparator as a
second reference,
and maybe another GPS based unit..... oh my :-)  Anyone looking to
sell/trade that LORAN
comparator?


Shaun
--
smerriga@compusmart.ab.ca