[time-nuts] GPSDO time constant

Mark Sims holrum at hotmail.com
Thu Jan 8 20:17:59 UTC 2009


In the world of precision scales you can often beat the many of the manufactures specs by an order of magnitude by adjusting and calibrating the scale in the exact location and orientation where it will be used (and not moving it or afterwards).  Some of  the adjustments involve moving rather crudely threaded mechanical adjustments the equivalent of a few wavelengths of light.  There is no way to actually make the adjustments other than trial and error...  move it enough times and it will eventually wind up in the right place...  and hysteresis and backlash are a bitch...

The alignment spec for the color monitor in  the HP16500 logic analyzers says to face the unit to the west when adjusting it (but they don't say which end to point west).  Also some of the adjustments are on the bottom of the monitor and others are on the side.  You usually make the adjustments with the unit on its side...  but nobody ever runs the unit in that orientation.

------------
I've heard that the xtal oscillator cal procedure for some HP test
equipment says that the instrument should be in the same position as when
it's operating.  For heavy rack equipment that means you lay on a
mechanics creeper when making the adjustment rather than flipping the
instrument 90 degrees on a bench.


_________________________________________________________________
Windows Live™: Keep your life in sync.
http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009


More information about the time-nuts mailing list