7-50
Operating Concepts
Measurement Calibration
The analyzer’s test set can measure both the forward and reverse characteristics of the test
device without you having to manually remove and physically reverse the device. A full
two-port error model illustrated in Figure 7-38. This illustration depicts how the analyzer
effectively removes both the forward and reverse error terms for transmission and
reflection measurements.
Figure 7-38 Full Two-Port Error Model
A full two-port error model equations for all four S-parameters of a two-port device is
shown in Figure 7-39. Note that the mathematics for this comprehensive model use all
forward and reverse error terms and measure d v alues. Thus, to perform full
error-correction for any one parameter, all four S-parameters must be measured.
Applications of these error models are provided in the calibration procedures described in
Chapter 5 , “Optimizing Measurement Results.”
Enhanced Response Calibration Error Model Enhanced response calibration uses
the same error model as the forward configuration portion of Figure 7-38. In the response
portion, the source and load match effects are fully- accounted f or gi ving the same accuracy
to the forward tracking term (ETF) as the two-port calibration. During the measurement,
the enhanced response calibration performs a correction which is mathematically the same
as setting the values of ELF, ELR, ESR, EXR, EDR to zero (0) and the values of ERR and ETR
to one (1) in the equations for S11 and S21 shown in Figure 7-39.