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Specify the adapter
It is important to recognize that the nominal electrical delay of the adapter must be known
within ±
1
/4 wavelength at each measurement frequency. The electrical delay of the adapter
must be known because the adapter removal calculations include taking a square root of a
complex number. In order to determine the correct sign of the root, the algorithm uses the
adapter length to place the result in the correct quadrant. The adapter’s electrical length
must be entered into one of the Agilent 8510 cal kit definitions.
Measure the adapter
Measure the nominal electrical delay of the adapter as follows:
1. With Port 1 configured so that the adapter may be connected, perform a simple S
11
Response calibration at Port 1 using a short circuit.
2. Connect the adapter to Port 1 and terminate the adapter with a short circuit.
3. Measure the electrical delay of the adapter. Select PHASE, RESPONSE MENU,
ELECTRICAL DELAY, then adjust electrical delay to achieve a flat trace. If the adapter is
a waveguide device, select waveguide delay and enter the correct cutoff frequency.
One-half the measured electrical delay value is the actual nominal length of the adapter. If
the short circuit used to terminate the adapter is offset, remember to subtract its electrical
length from the measurement.
Modify the cal kit
Next, modify one of the cal kits to include this adapter definition as follows:
1. Select the cal kit to include the adapter definition by pressing CAL, MORE,
MODIFY <cal kit label>.
2. Refer to the cal kit Standard Assignment table in the cal kit manual and choose an
unused standard, 20 for instance. Press DEFINE STANDARD, then enter 20, x1, then
select the standard type by pressing DELAY/THRU.
3. Enter the electrical delay of the adapter by pressing SPECIFY OFF SET, OFFSET DELAY,
then entering the value for electrical delay measured above. If the adapter is a wave
guide device, press WAVEGUIDE, then press MINIMUM FREQUENCY and enter the
cutoff frequency. Press STD OFFSET DONE.
4. Next, enter a descriptive label for the adapter by pressing LABEL STANDARD then using
the knob and the Title menu. Press TITLE DONE. Now press STD DONE (DEFINED).
(It is not necessary to specify any other characteristics of the adapter except Offset
Delay, Minimum and Maximum Frequency, and Coax or Waveguide.)
5. Now press SPECIFY CLASS, MORE, MORE, then SPECIFY: ADAPTER and enter the
standard number of the adapter, 20, x1. Press CLASS DONE.
6. Enter an appropriate class label by pressing LABEL CLASS, MORE, MORE, ADAPTER
then using the Title menu.
7. Enter an appropriate label for the calibration kit by pressing LABEL KIT and defining the
title using the Title menu.
8. Finally, press KIT DONE (MODIFIED) to save this new cal kit definition.
This cal kit is now ready to be used in the adapter removal procedure.