I can speak for what HP/Agilent did for calibration of Tektronix ETE manually and using Metcal software. Most of the Metcal programs for Tektronix were written by an HP engineer thoroughly trained on Metcal, or written by Tektronix engineers.
The Metcal trained engineer would use the TEK manual cal procedure, automating the instrument and measurement where possible, or prompting the person doing the cal through the manual procedure. Other TEK ETE was done manually using the Tek
manual and cal procedure. I can speak for the 11302A mainframes and plugins, 75-125 page cal procedures. I have done cal procedures on over 50ea. 11302A and CSA803 mainframes and plugins. After the 5th one in a row your attention and focus is shot, and typically it is 40+ hrs. later in you life, definitely not my favorite instrument to calibrate, especially with the SD26 plugins.
Don Bitters
