Reflection Tracking (Erf And Err) - Agilent Technologies 8719ET Service Manual

8719ET/20ET/22ET Error Terms
8719ES/20ES/22ES Error Term Descriptions
RF Network Analyzers

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 (S11, 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 roll-off below 500 MHz, which is typically −18 dB at
100 MHz, and −25 dB at 50 MHz.
Significant System Components. The open and short calibration devices have 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 A or B input paths first if only one reflection tracking term is
affected.
Affected Measurements. All reflection measurements (high or low return loss) are
affected by the reflection tracking errors.
Figure 11-3 Typical ERF/ERR
Service Guide 11- 13