"David L. Jones" wrote in
oups.com:

On Mar 4, 12:38 pm, MassiveProng
wrote:
On 2 Mar 2007 15:09:30 -0800, "David L. Jones"
Gave us:

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

It doesn't matter how many "places" you "spot check" it, you are not
going to get the accuracy of your comparison standard on the device
you intend to set with it. What you do is take the basic INaccuracy
of the device needing to be set, and add to it the basic INaccuracy of
the standard to which you are setting it. You CANNOT get any closer
than that. So, a 0.5% meter, and a 0.5% scope cannot be used together
to make the scope that accurate. You need a *finer* standard than the
accuracy level you wish to achieve.

You need to understand that as a basic fact, chucko.

LMAO!
If I use 0.5% accurate meter to adjust a something, then the accuracy
of that adjusted device at that point in time at that adjusted value
*becomes* 0.5%.

Until you turn off the "something"(DUT),the ambient temp changes,or some
hours pass(drift);then it reverts to it's specified accuracy.

4X better is the minimum for a cal standard over the DUT.
Any less has to be noted on the cal certificate.

--
Jim Yanik
jyanik
at
kua.net