3. Operating Instructions
Figure 3.33.
S
11
return loss plot (orange) and TDR trace (red) of a 2.4 GHz WiFi
antenna. The return loss is calculated on the portion of the TDR trace between the
cursors
1. Create an S
11
return loss plot using the procedure as described on page 49.
2. Select the
S
11
Options
menu, then
Pre-Filter Options
.
3. Toggle
Use this filter
to apply filter to the S
11
trace.
4. Toggle
Common Mode Subtraction (CMS)
to apply this option to the S
11
trace.
5.
Filter/CMS Offset Ratio
is the start of the Aberration Filter and/or Common Mode
Subtraction relative to the S
11
trace test plane. The default value is 1.66, and is ideal in
most cases.
6.
Frequency (MHz)
is the aberration filter frequency. The default value is 200, and is ideal in
most cases.
7. Press
OK
to change the settings to those set above. The S
11
trace will update using the
new settings.
3.11.18.2. Return Loss (S
11
) Post-Filter
The Post-Filter can reduce excess noise in the S
11
trace. To enable or disable the setting, do the
following:
1. Create an S
11
return loss plot using the procedure as described on page 49.
2. Select the
S
11
Options
menu, then
Post-Filter Options
.
3. Toggle
Use this filter
to apply filter to the S
11
trace.
4.
Frequency (MHz)
is the noise filter frequency. The default value is 20,000 (20 GHz), and is
ideal in most cases.
5. Toggle
Apply Hanning
to apply a Hanning Window to the filter.
6. Press
OK
to change the settings to those set above. The S
11
trace will update, although it
might not look visually different, depending on the settings.
3.11.18.3. Return Loss (S
11
) Phase Correction
Phase Corrections reduces phase error oscillation in the S
11
trace. To enable or disable the
setting, do the following:
CT100B TDR Cable Analyzers Operator’s Manual
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