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by using the following assumptions:
V 0
The error in doing this is:
–
So if
ignored. In practice
By substituting equation 3 into equation 1 and manipulating the result you get:
0
This quadratic can be solved to give equation 2.
The definitions of the terms in equation 2 are:
– V
– V
– V
– R is the resistance of the mount resistor in the Keysight 432A power meter
– Calibration Factor is the value of the thermistor mount at 50 MHz.
Equipment
– Test power meter: Keysight 432A.
– Thermistor Mount: Keysight 478A Option H75 or H76.
– Digital Voltmeter (DVM): Keysight 3458A.
Keysight E4416A/E4417A Power Meters Service Guide
2
2
V 1
=
V 1 V 0
(
–
–
–
2
2
⎛
V 1
+
V 0
2V 1 V 0
–
⎝
2V
V
V
) 2V
«
(
–
0
1
0
V
2
=
V 1 V 0
2V comp V 1 V 0
(
)
–
–
is the voltage measured between V
0
after the Keysight 432A has been zeroed.
is the voltage measured between V
1
power is approximately 1 mW.
is the voltage between the Keysight 432A V
comp
ground with power applied.
2
)
2
2
⎞
⎛
⎞
V 0
V 1
=
–
–
–
⎠
⎝
⎠
, that is,
V
V
(
)
–
comp
1
0
and
~
4Volts
V
comp
+
(
)
–
comp
comp
2
2V 0
+
2V 1 V 0
=
2V 0 V 1 V 0
then the error can be
V
«
V
0
comp
. The eror is less than 0.01%.
<
400
μ
V
0
3
–
4 10
)R CalibrationFactor
(
(
and V
with no power applied and
RF
and V
with power applied. This
RF
connector and chassis
comp
Adjustments
3
(
)
–
)
79
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Troubleshooting
