Giga-tronics 8650A Series, Operation Manual

Page: 201 / 240

Performance Verification
Manual 31470, Rev. E, April 2001 4-3
4. Set the 432A RANGE switch to COARSE ZERO, and adjust the front panel COARSE ZERO
control to obtain a zero (
±
2% F.S.) meter indication.
5. Set the DVM to a range that results in a resolution of 1
µ
V and connect the positive and
negative input, respectively, to the V
COMP
and V
RF
connectors on the rear panel of the 432A.
6. Fine zero the 432A on the most sensitive range, then set the 432A range switch to 1 mW.
7. Record the DVM indication as V
0
.
8. Turn ON the 8650A Calibrator RF power as follows:
Press [ Meter Setup ] [ Calibrator ] [ Frequency ], set to 50.0 MHz, press [ ON ] then [ OK ].
Record the reading shown on the DVM as V
1
.
9. Disconnect the DVM negative lead from the V
RF
connector on the 432A, and reconnect it to
the 432A chassis ground. Record the new indication observed on the DVM as V
COMP
.
10. Repeat Step 7, except select OFF to turn the Calibrator off.
11. Calculate the Calibrator Output level (P
CAL
) using the following formula:
where:
P
CAL
= calibrator output power reference level
V
COMP
= previously recorded value in Step 8
V
1
= previously recorded value in Step 7
V
0
= previously recorded value in Step 6
R= 200
Ω
(assuming HP478A-H75 mount)
Calibration factor = value for the thermistor mount at 50 MHz (traceable to the NIST)
12. Verify that the P
CAL
is within the following limits:
1 mW
±
0.019 mW (0.981 to 1.019 mW)
For record purposes, the measured value of P
CAL
can be entered on the Test Data Recording
Sheet located on page 4-9.
13. For Option 12, set the calibrator frequency to 1.000 GHz as in step 8 and repeat steps 9 through
12.
NOTE : Ensure that the DVM input leads are isolated from chassis ground
when performing the next step.
NOTE : The V
1
reading must be taken within 15 seconds after pressing [OK].
Otherwise, turn the Calibrator OFF and repeat steps 7 and 8.
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