3. Operating Instructions
3.11.13. First Derivative (Slope) Traces
The first derivative trace can be used for two main purposes. First, the first derivative trace can
be used to emulate the trace of a pulse-type TDR. Second, it may be used to remove the
baseline deviation of long or lossy cables caused by resistive loss, so that vertical gain can be
used to emphasize cable faults. To create a first derivative trace, use the following procedure.
1. Press the
SCAN
button. The
Scan
menu appears.
2. Press the
SELECT
button until the trace of interest is selected.
3. Select the
Math
option from the
Scan
menu. The
Math
menu will appear.
4. Select
1st Derivative
from the menu.
5. A new trace is created that displays the first derivative of the base trace. See Figure 3.30.
Figure 3.30.
First-derivative trace (yellow, bottom).
3.11.14. Second and Higher Order Derivative Traces
The
1st Derivative
function can be applied to First Derivative traces to create second (and
higher) order derivatives.
3.11.15. Vertical Reference (Vert. Ref.) Calibration
Use the vertical reference (Vert. Ref.) system to increase the accuracy of vertical measurements,
including impedance, reflection coefficient, and return loss. The
Vert. Ref.
feature can be used
with a direct connection, through impedance matching adapters, and using baluns. To calibrate
with the
Vert. Ref.
feature, use the following procedure:
1. Go to the
MENU
→
Measurement
menu.
2. Select the option for
Vert. Ref.
to display the
Vert. Ref.
menu.
3. Position the active cursor at the leftmost position where the
Vert. Ref.
should apply.
Typically, this will be the position where you will apply the open and short attachments in
step five. This position can be changed after the setup.
4. Select the
Set Vert. Ref
option.
CT100B TDR Cable Analyzers Operator’s Manual
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