Atek HP 8753D, User Manual, Page: 353 / 677

line standard becomes the measurement reference and, therefore , has to be assumed ideal (or
known and dened precisely).
At this point, the forward and reverse directivity (E
DF
and E
DR
), transmission tracking (E
TF
and E
TR
), and reection tracking (E
RF
and E
RR
) terms may be derived from the TRL error
terms . This leaves the isolation (E
XF
and E
XR
), source match (E
SF
and E
SR
) and load match
(E
LF
and E
LR
) terms to discuss .
Isolation
Two additional measurements are required to solve for the isolation terms (E
XF
and E
XR
).
Isolation is characterized in the same manner as the Full 2-port calibration. F orward and
reverse isolation are measured as the leakage (or crosstalk) from port 1 to port 2 with each port
terminated. The isolation part of the calibration is generally only necessary when measuring
high loss devices (greater than 70 dB).
Note
If an isolation calibration is performed, the xture leakage must be the
same during the isolation calibration and the measurement.
Figure 6-52. 8-term TRL error model and generalized coecients
Application and Operation Concepts 6-87