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Transmission Magnitude Uncertainty
An analysis of the error model, located at the end of this appendix, yields an equation for
the transmission magnitude uncertainty. The equation contains of the order terms
and some of the significant second order terms. The terms under the radical are random in
character and are combined on an RSS basis. The terms in the systematic error group are
combined on a worst case basis. In all cases, the error terms are treated as linear absolute
magnitudes.
Transmission magnitude uncertainty (forward direction) Etm =
= Syst + (Drift and
Systematic
Efc + + + + +
Random = + +
= + + +
= + + +
Nt =
Drift and Stability =
where
= Connector repeatability (transmission) port 2
= Connector repeatability (reflection) port 2
Efnt = effective noise on trace
Efnf effective noise floor
= connector repeatability (reflection)
Crtl = connector repeatability (transmission)
Ctml = cable 1 transmission magnitude stability
cable 2 reflection magnitude stability
= cable 2 reflection magnitude stability
Dmsl drift source to port
Efs = effective source match error
Eft = effective transmission tracking error
Efl = effective load match error
Efc = effective crosstalk error
The detailed equation for each of the above terms is derived from the signal flow model,
located at the end of this appendix.
Determining System Measurement