China Electronics Technology Instruments AV3672 Series, User Manual

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7 Calibration
7.1 Calibration Overview
209
7 Calibration
Calibration can help to reduce the measurement error. This chapter includes the following contents:
●
Calibration overview
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●
Selection of calibration type
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Calibration guide
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●
High-accuracy measurement calibration
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Measurement error
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●
Editing of calibration kit definition
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Calibration standards
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TRL calibration
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Fixture compensation calibration
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Electronic calibration
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7.1 Calibration Overview
Measurement calibration is a process to determine the system errors according to the standards of the existing
measurement characteristics and then eliminate the influence of system errors during measurement of the DUT. It
can help to reduce the measurement error and improve the measurement accuracy of the analyzer.
7.1.1 Definition of Calibration
Calibration is a process to eliminate one or more system error(s) with the error model. The error item of the error
model is solved by measurement according to high-quality calibration standards (including the open-circuit device,
short-circuit device, load and through type part). See system error details in “
7.5.3 System Error
” of “
7.5
Measurement Error
” in this chapter.
Select the appropriate calibration method according to the measurement type and accuracy requirements. See
details in “
7.2 Selection of Calibration Type
”.
Various kinds of calibration can be done according to the calibration guide of the calibration. See details in “
7.3
Calibration Guide
”.
The measurement accuracy after calibration depends on the quality of the calibration standard and the model
definition accuracy of the standard calibration kit in the calibration kit definition file.
The calibration kit definition
file is saved in the analyzer. In order to ensure the measurement accuracy, the actual calibration kit must
conform to the requirements of the calibration kit definition file.
See accurate calibration details in “
7.4 High-
accuracy Measurement Calibration
”.
The user must correctly define the calibration standard in the calibration kit definition file of the user so as to
use the custom calibration kit (e.g. for fixture measurement calibration). See details in “
7.6 Editing of
Calibration Kit Definition
”.
7.1.2 Significance of Calibration
It is impossible to make an ideal analyzer requiring no error correction from the perspective of hardware circuit.
Even if error correction can be ignored in good hardware circuits, the costs will be high. In addition, the
measurement accuracy of the analyzer is largely influenced by external accessories. The amplitude and phase
changes of test components such as the connecting cable and adapter will affect response the real response of the
DUT. Therefore, the best method is to balance the hardware performance and cost, make high-quality hardware as
practical as possible and improve the measurement accuracy by calibration.
7.1.3 Applications of Calibration
➢
High measurement accuracy is expected.