HP E4418A User Manual

Adjustments
Power Reference Oscillator Level Adjustment
HP EPM-441A/442A Service Guide 3-7
For this adjustment the following mathematical assumptions are made:
Equation 1:
can be manipulated to give equation 2:
by using the following assumptions:
The error in doing this is:
So if , that is, then the error can
be ignored. In practice and . The error is less
than 0.01%.
By substituting equation 3 into equation 1 and manipulating the result
you get:
This quadratic can be solved to give equation 2.
The definitions of the terms in equation 2 are:
•V
0
is the voltage measured between V
comp
and V
RF
with no power
applied and after the HP 432A has been zeroed.
•V
1
is the voltage measured between V
comp
and V
RF
with power
applied. This power is approximately 1 mW.
•V
comp
is the voltage between the HP 432A V
comp
connector and
chassis ground with power applied.
• R is the resistance of the mount resistor in the HP 432A power
meter.
• Calibration Factor is the value of the thermistor mount at
50 MHz.
P
meas
2V
comp
V
1
V
0
–()V
0
2
V
1
2
–+
4R CalibrationFactor
()
-----------------------------------------------------------------------------------=
V
1
V
comp
V
0
V
comp
2
10()
3–
– 4R
()CalibrationFactor()–+=
V
0
2
V
1
2
– V
1
V
0
–()–
2
=
V
1
2
V
0
2
2V
1
V
0
–+()– V
0
2
V
1
2
–()– 2V
0
2
– 2V
1
V
0
+2V
0
V
1
V
0
–()==
2V
0
V
1
V
0
–()2V
comp
V
1
V
0
–()«V
0
V
comp
«
V
comp
4Volts~V
0
400µV<
0V
1
V
0
–()
2
2– V
comp
V
1
V
0
–()=410
3–
()R CalibrationFactor()+
4402serv.book Page 7 Monday, March 11, 2002 11:34 AM

HP E4418A Specifications

General

Brand	HP
Model	E4418A
Category	Measuring Instruments
Language	English