Agilent Technologies HP 8719D Service Manual page 324

Reflection Tracking (ERF and ERR)
Reflection tracking is the difference between the frequency response of the
reference path (R path) and the frequency response of the reflection test
path (A or B input path). These error terms are characterized by measuring
the reflection (Sl1 , S22) of the open and the short during the measurement
calibration. Note that coupler response is included in this error term. Typically
this appears as a slope of O/-5 dB from 0.84 GHz to 40 GHz and a roll-off below
0.84 GHz, which is typically -3 dB at 500 MHz, -15 at 100 MHz, and -20 at 50
M H Z .
an effect on reflection tracking. But large variations in this error term may
indicate a problem in one of the signal paths. Suspect the R signal path if the
problem appears in both ERF and ERR. Troubleshoot the
if only one reflection tracking term is affected.
Affected Measurements.
are affected by the reflection tracking errors.
The open and short calibration devices have
All reflection measurements (high or low return loss)
Figure 11-3. Typical ERJVERR
A
or B input paths tist