Agilent Technologies 4395A, Manual Change

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Calibration for Network Measurement
Frequency Response (Tracking)
This is the vector sum of all test setup variations in which magnitude and phase change as a
function of frequency . This includes variations contributed by signal separation devices , test
cables , and adapters , and variations between the reference and test signal paths . This error is a
factor in both transmission and reection measurements .
F or further explanation of systematic error terms and the way they are combined and
represented graphically in error models , see the later section, titled A ccuracy Enhancement
Fundamentals - Characterizing Systematic Errors .
Compensation for Measurement Errors
There are twelve dierent error terms for a two-port measurement that can be corrected
by accuracy enhancement in the analyzer . These are directivity , source match, load match,
isolation, reection tracking, and transmission tracking, each in both the forward and reverse
direction. The analyzer has several dierent measurement calibration routines to characterize
one or more of the systematic error terms and remove their eects from the measured
data. The procedures range from a simple frequency response calibration to a full two-port
calibration that eectively removes all twelve error terms .
The Response Calibration eectively reduces the frequency response errors of the test setup
for reection or transmission measurements . This calibration procedure may be adequate
for measurement of well-matched low-loss devices . This is the simplest error correction to
perform, and should be used when extreme measurement accuracy is not required.
The Response and Isolation Calibration eectively removes frequency response and crosstalk
errors in transmission measurements , or frequency response and directivity errors in reection
measurements . This procedure may be adequate for measurement of well-matched high-loss
devices .
The S
11
and S
22
One-P ort Calibration procedures provide directivity , source match, and
frequency response vector error correction for reection measurements . These procedures
provide high accuracy reection measurements of one-port devices or properly terminated
two-port devices .
The Full Two-P ort Calibration provides directivity , source match, load match, isolation,
and frequency response vector error correction, in both forward and reverse directions , for
transmission and reection measurements of two-port devices . This calibration provides
the best magnitude and phase measurement accuracy for both transmission and reection
measurements of two-port devices , and requires an S-parameter test set.
The One-P ath Two-P ort Calibration provides directivity , source match, load match, isolation,
and frequency response vector error correction in one direction. It is used for high accuracy
transmission and reection measurements using a transmission/reection test kit, such as the
87512A, B . (The DUT must be manually reversed between sweeps to accomplish measurements
in both the forward and reverse directions .)
All the calibration procedures described above are accessed from the 4
CAL
5 key .
A-44 Basic Measurement Theory