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Chapter 4
Calibration and Compensation
Outline of Calibration and Compensation Functions
Outline of Calibration and Compensation Functions
Any measuring instrument, however sophisticated it may be, has a certain degree of error
in actual use. The functions of calibration and compensation of the E4991A minimize
possible errors and assure higher measurement accuracy.
Types of Calibration and Compensation
The E4991A has five calibration/compensation functions as shown in Table 4-1.
Table 4-1
Calibration/Compensation Functions of E4991A
Calibration/compensation
functions
Execution Method
Effect
Calibration of open/short/load
All calibration data are measured by
connecting three standards (open, short,
and load) one-by-one to the desired
reference plane (connector). This
reference plane is called the calibration
reference plane.
The error factors within the area from the
instrument body to the calibration
reference plane are removed. If calibration
is performed for the connector of the DUT,
it is not necessary to execute any further
calibration/compensation.
Calibration of low-loss capacitor
The calibration data are measured by
connecting the low-loss capacitor to the
calibration reference plane after
completing the open/short/load
calibration. This can only be executed
when the 7-mm connector is used as the
calibration reference plane.
This decreases high Q (low-loss
coefficient) above the frequency band near
1 GHz, which is difficult to decrease by
only using open/short/load calibration.
Port extension compensation
*1
When the port is extended from the
compensation reference plane by a coaxial
cable, enter the delay time (sec.) of the
extension as a numerical value and regard
the corresponding extended portion as a
distributed parameter circuit without loss.
This compensates additional error caused
by phase shift in the area of the port
extended by the coaxial cable.
Fixture electrical length
compensation
Electrical length is entered as a numerical
value. Since the electrical length of an
exclusive-use test fixture is registered in
the E4991A, the necessary electrical
length can be set by simply selecting the
model number of the test fixture used.
This compensates additional errors caused
by phase shift at the test fixture.
Compensation of open/short
All compensation data are measured after
bringing the tested device’s connecting
terminal to the open and/or short state.
This removes any additional measurement
error caused by residual impedance in the
test fixture.
*1.Port extension compensation is not required when an Agilent text fixture is directly connected to the 7-mm termi-
nal of the test head.
Summary of Contents for E4991A
Page 6: ......
Page 24: ...18 Contents ...
Page 80: ...74 Chapter3 Setting Measurement Conditions Averaging Measurement Results ...
Page 220: ...214 Chapter9 Setup and Use of Control Management Functions System Recovery ...
Page 338: ...332 AppendixB Probe Station Connection Kit Option 010 OPEN SHORT LOAD Calibration ...
Page 428: ...422 AppendixD Menu References Menu References ...
Page 482: ...476 AppendixI Messages Wait measuring comp standard ...