Bird Technologies 5015 Series-Manual User Manual
Page 22
10
Note:
If a source with a 1.30:1 VSWR was
used instead, the mismatch uncertainty would be:
Using a lower VSWR source can drastically reduce the
mismatch uncertainty. Keep in mind that the typical
VSWR of the Model 5011 is 1.03:1, which gives a much
lower mismatch uncertainty.
Example - With the 1.50:1 source, the mis-
match uncertainty would be:
To determine the total uncertainty of the measure-
ment, combine the RSS uncertainty with the mis-
match uncertainty using the RSS method. Square the
RSS uncertainty, add it to the square of the mismatch
uncertainty, and take the square root.
Using Example 1 in Table 3 with a source VSWR of
1.50 and a TPS VSWR of 1.20, the total uncertainty
would be:
For example 2, the total uncertainty would be 6.82 %.
ρ
s
1.30
1
–
(
) 1.30 1
+
(
)
⁄
0.130
=
=
ρ
1
1.20
1
–
(
) 1.20 1
+
(
)
⁄
0.091
=
=
MU
1
0.130
0.091
Ч
+
(
)
2
1
–
[
] 100
2.39
±
=
Ч
=
ρ
s
1.50
1
–
(
) 1.50 1
+
(
)
⁄
0.200
=
=
ρ
1
1.03
1
–
(
) 1.03 1
+
(
)
⁄
0.015
=
=
MU
1
0.200
0.015
Ч
+
(
)
2
1
–
[
] 100
0.59
±
=
Ч
=
5.00
2
3.67
2
+
6.20 percent
(
)
=