where
w
Efnt = effective noise on trace
w
Efnf = effective noise floor
n
Crtl = connector repeatability (transmission)
n
Crrl
= connector repeatability (reflection)
n
Ctml = cable 1 transmission magnitude stability
n
Crml
= cable 1 reflection magnitude stability
w
Cm12
= cable 2 reflection magnitude stability
n
Dmsl = drift
magnitude/°C
source to port 1
n
Efs = effective source match error
n
Efr = effective reflection tracking error
n
Efl = effective load match error
n
Efd
=
effective directivity error
n
Crr2
= Connector repeatability (reflection)
The detailed equation for each of the previous terms is derived from the signal flow model,
located at the end of this appendix.
Reflection Phase Uncertainty (Erp)
Reflection phase uncertainty is determined from a comparison of the magnitude uncertainty
with the test signal magnitude. The worst case phase angle is computed. This result is
combined with the error terms related to thermal drift of the total system, port 1 cable
stability, and phase dynamic accuracy.
+
2Cpfl
x f + Dpsl + Dpfsl x f
where
Cpfl
=
cable phase/frequency port 1
Dpsl
=
drift phase/degree source to port 1
Dpfsl
=
drift phase/degree/frequency source to port 1
84
Determining System Measurement Uncertainties
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