Appendix C

Cal coefficients model

Offset devices like offset shorts and offset opens can be modeled by the following signal flow graph :

Figure 1 Signal flow graph model of offset devices

The offset portion of the open or short, is modeled as a perfectly uniform lossy air dielectric transmis- sion line. The expected coefficient of reflection, Γ, of the open or short then can be solved by signal flow graph technique.

Equation 1

The terms Zo, and are related to the cal coefficients - Offset Zo, Offset Loss, and Offset Delay - as follows:

Recall that

Equation 2

L ≈ L0 + ωR

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Agilent Technologies 8510 manual Appendix C Cal coefficients model, Equation