Calibration/Normalization; Types Of Measurement Errors; Open/Short Calibration - Agilent Technologies PSA Series Manual

Calibration/Normalization

Types of Measurement Errors

There are three basic sources of measurement error: systematic,
random and drift.
• Systematic Errors
— are due to imperfections in the analyzer and the test setup
— are assumed to be time invariant (predictable)
— are characterized by the calibration, and can be removed during
measurements
• Random Errors
— vary with time in a random fashion (unpredictable)
— are mainly a result of instrument noise (source phase noise,
analyzer sensitivity)
— cannot be removed
• Drift Errors
— are due to instrument or test-system performance changes after a
calibration has been done (unpredictable)
— are primarily caused by temperature variations
— can be removed by re-doing the calibration
So doing a calibration before making the measurement improves the
measurement accuracy. Any time you change the frequency, power
settings, or cables within a measurement, you must repeat the
calibration routine.

Open/Short Calibration

An open/short calibration is used for reflection measurements and only
corrects for system tracking errors (source match and reflection
tracking). This type of calibration is essentially a normalized
measurement where a reference trace is stored in memory. This
memory trace data is then subtracted from later measurement data.
Press ,
Source Open/Short Cal
Chapter 2
Measurement Concepts
Calibration/Normalization
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