Note
The HP
8496A
step attenuator (Option 001,
H18)
comes with a
special calibration that supports the measurement uncertainties
expressed in the test record for this performance test.
The special calibration consists of two measurements The
hrst
is a measurement of the attenuation at each step. The data
reported for this measurement have the following uncertainties:
n
f0.006
dB
from 0 to 40
dB
w
f0.015
dB
from
>40
to 80
dB
n
f0.025
dB
from
>80
to 90
dB
n
f0.05
dB
>90
dB
The second calibration measurement characterizes match
stability between attenuator settings for each attenuator port.
The vector difference of
S11
or
($2)
between the reference
attenuation step and
all
the other steps is measured. The
magnitude of this difference is certified to be ~0.0316 (>30
dB).
Note
The HP
8496A
used for this test
wiU
have known attenuator
errors for attenuations up to 100
dB
using a test frequency of
30 MHz. The attenuation used as a reference is 0
dB.
If the
available calibration data is not expressed as attenuation errors,
it can be converted to such a form by the following equation:
(actual attenuation)
-
(expected attenuation) = attenuator error
Actual attenuation values that are greater than the expected
attenuation values
wiII
result in positive errors Actual
attenuation values that are less than the expected attenuation
values
wiII
resuh
in negative errors.
2-76 System Veriiication and
Performance Tests
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