There are several factors that cause difference between simulated and actual test data. Below are the most common causes:

• Actual interfaces during testing will be different from the model.

• Dielectric constants and dimensions of cables are variable and cable is modeled as perfect.

• Dielectric constants of different materials used as insulators (i.e.: delrin, lcp) are not precisely known.

• Calibration kits for all types of connectors are not available and therefore gating is often used in taking data.

• Small air spaces are usually not modeled as they greatly increase the complexity of the model. They are typically filled with dielectric.

• Actual assembly of the device can result in components compressing (ie: press fits) which may cause the longitudinal and relational position of the components to be different from the model.

• Generally, small radii are not modeled. They are replaced with chamfers or even eliminated completely.

• Connectors are modeled using nominal dimensions. Actual parts have tolerances.

• The adaptive frequency is a single frequency usually about 80% of the upper frequency limit, but the analysis is usually swept over a broad frequency range.

• Crimping can deform cables in an extremely variable manner and this is usually not modeled.