Hi to the HP-Enthusiasts, Dear Aaron!
On the weekend Aaron approached me because of the work I have done to
re-program my HP8756A scalar analyzer with fresh calibration data.
My analyzer lost data quite quickly and that was because one of the
caps developed a signigicant leakage current. So I replaced all of them
and added a larger Li battery to the CPU board.
For programming, I used (in the 2000s) a sun workstation and the sbus
GPIB adapter which was in there, so that code is not of much use
nowadays. But the procedure was as follows:
Using a calibrated HF-voltmeter, I created a table of the output power
of my 8350B generator for all attenuator steps. Than I connected
the detector to the 8350B and made a measurement using the un-
calibrated 8756A (with cleared calibration data).
From that, I calculated correction polynomials for all three channels,
(taking into account the frequency and the correction value printed on
the detector head for the frequency I was running at).
In a last step I wrote the polynomal into the 8756A and after that it
gave the correct readings as measured with the HF-voltmeter.
Attached is the C source file for your amusement (there you can see
how the polynomial gets written). Should not be hard porting that
to a modern platform.
(1) USE AT YOUR OWN RISK
(2) Would be happy if you mention my work ;-)
Best wishes,
Erik. www.baigar.de
P.S. Of course a much better method would be analyzing the 8757 cal
program (which does not work with the 8756A of course!)...
...on how to drive the 11613B calibrator...
...and with the knowledge from my c code creating a new, nice
calibration software (preferrably for linux ;-)). Actually
I have got one of the 11613Bs, but the project never has
taken off...
P.P.S. The only reason to bother with the 8756A is, that I have the
equipment doe measurements up to 18G which is not the case
for my VNWA.
-----------------------------------------------------------------------
''~``
( o o )
+--------------------------.oooO--(_)--Oooo.-------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik@... +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
Dave McGuire