Agilent Technologies 8719D User Manual page 334

Figure 6-33. Sources of Error in a Reflection Measurement
signal (I) from the reflected signal (R), then taking the ratio of the two values (see F'igure 6-34).
Figure 6-34. Reflection Coefkient
However, a.ll of the incident signal does not always reach the unknown (see Figure 6-35).
Some of (I) may appear at the measurement system input due to leakage through the test
set or through a signal separation device. Also, some of (I) may be reflected by imperfect
adapters between a signal separation device and the measurement plane. The vector sum of
the leakage and the miscellaneous reflections is the effective dire&iv&y, Enr. Understandably,
the measurement is distorted when the directivity signal combines vectorally with the actual
reflected signal from the unknown, &IA.
Application and Operation Concepts