7-45
Operating Concepts
Measurement Calibration
Figure 7-30 Measured Effective Directivity
Next, a short circuit termination whose response is known to a very high degree is used to
establish another condition as shown in Figure 7-31 .
Figure 7-31 Short Circuit Termination
The open circuit gives the third independent condition. In order to accurately model the
phase variation with frequency due to fringing capacitance from the open connector, a
specially designed shielded open circuit is used for this step. (The open circuit capacitance
is different with each connector type.) Now the values for EDF, directivity, ESF, source
match, and ERF, reflection frequency response, are computed and stored. See Figure 7-32.