Boonton 4500B Peak Power Meter - Manual (Page 339)

Boonton 4500B RF Peak Power Analyzer
Maintenance 7-7
8. Set the 4500B calibrator to 0 dBm (CW) by selecting Calibrator > Set Level > 0.0 dBm,
Calibrator > Cal Mode > CW and Calibrator > Cal Output > ON. Record the multimeter
indication in VDC to six decimal places. Label this measurement V
1
.
9. Disconnect the multimeter negative lead from the V
rf
and connect the lead to the 432A chassis
ground. Record the multimeter indication in VDC to four decimal places. Label this measurement
V
comp
.
10. Calculate the 4500B calibrator‘s 0 dBm power output (Po) using the following formula:
(2 × V
COMP
× (V
1
 V
O
)) + (V
O
2 – V
1
2 )
P
O
=
4 × R × EffectiveEfficiency
Where:
P
o
= 4500B calibrator‘s 0 dBm power output
V
comp
= Value recorded in step 9.
V
1
= Value recorded in step 8.
V
0
= Value recorded in step 7.
R = Value recorded in step 1.
Effective Efficiency = Calibration factor at 1 GHz for the thermistor mount
(traceable to NIST).
11. Verify P
o
is between 0.985 mW and 1.015 mW.
12. If P
o
is in tolerance, record P
o
and disconnect all test equipment. If P
o
is out of tolerance, go to
Section 7.7 to re-calibrate.
Sensor Return Loss Verification
Table 7-4 lists the Model 4500B sensors and return loss specifications for each frequency range.
Referring to Subsection 7-5, select the test equipment appropriate for the frequency range of your
sensor(s) and measure sensor return loss. Photocopy Table 7-4 and use it to record the minimum
return loss for each range applicable to your sensor(s). Attach the completed table to the Checklist.
Sensor Linearity Performance Verification
Verify sensor linearity with the internal calibrator by measuring the deviation from a linear
response at various levels. The pulse and CW modes are verified separately. Measurement error at
low power levels is dominated by the noise and drift of the power sensor. The tolerances listed in
table 7-5 through 7-10 reflect the combination of linearity error, noise, and drift.
Before verifying sensor linearity, select and photocopy those Tables (7-5 through 7-10) that apply
to your sensor and use them to record the measurement data. Attach the completed tables to the
checklist.