[time-nuts] 5370B arrived - any FAQ

[John Miles]

> I would suggest you go through the detailed alignment procedures even
> though the unit passes the operational checks. These units almost always
> have drifted out of alignment in the analog front-end unless you were
> lucky enough to get a freshly-calibrated one. You can usually
> significantly improve channel-to-channel trigger consistency and lower
> the jitter by doing so. It's a tedious process, and some of the pots are
> virtually impossible to reach, as are some of the test points, but it's
> worth the pain. The theoretical one-sample measurement accuracy is 20ps,
> but a non-adjusted unit can add many tens of ps of jitter. HP states a
> typical jitter of 35ps; with very careful tweaking, you can get better
> than that; mine reports 21-23 ps averaged over 1000 samples. (I'm not
> entirely sure I believe that, though)

I actually think you're better off not touching anything except the trigger
level adjustments unless there's a specific problem, such as self-test
jitter above 20 to 30 ps.  Aligning the interpolators properly requires an
8082A pulse generator and a very fast scope.

The front end can be challenging to align but it does need to be checked
carefully with respect to the operation of all the slide switches.  With
luck, nothing needs to be done to it.

-- john, KE5FX