User Manual

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×+()
2
1–[]100 2.39±=×=
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×+()
2
1–[]100 0.59±=×=
5.00
2
3.67
2
+6.20percent()=