7-43
Operating Concepts
Measurement Calibration
This re-reflection effect and the resultant incident power variation are caused by the
source match error, ESF as shown in Figure 7-27.
Figure 7-27 Source Match ESF
Frequency response (tracking) error is caused by variations in magnitude and phase
flatness versus frequency between the test and reference signal paths. These are due
mainly to coupler roll off, imperfectly matched samplers, and differences in length and loss
between the incident and test signal paths. The vector sum of these variations is the
reflection signal path tracking error, ERF as shown in Figure 7-28.
Figure 7-28Re flection Tracking ERF
These three errors are mathematically related to the actual data, S11A, and measured
data, S11M, by the following equation:
S11MEDF
S11AERF
1ESF S11A
–
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