Figure 3 15: The Set Zero Pop Up Menu - Tektronix 11801C User Manual

11801C User Manual
Selecting Cursor Types
At the top of the Cursor Type pop up menu, you can select from four cursor
types. If you select Vertical Bars, Horizontal Bars, or Paired Dots, the
11801C removes the pop up menu and shows the selected cursors. The
knobs control the cursor positions.
If you select Split Dots, the pop up menu stays on the display, and the
lower half of the pop up menu is active. The lower menu shows a selector
for each displayed trace (for example Trace 1, Trace 2). The selector for the
displayed trace is highlighted.
At this point, both split dot cursors are assigned to the selected (highlighted)
trace. To assign the second (right most) cursor to a different trace, touch the
selector for that trace. This action removes the pop up menu and moves the
second cursor to the selected trace.
Cursor Calibration
Cursor readout can be referenced to a user set horizontal point. This is
useful for making distance or time measurements using TDR or TDT. To
specify cursor readout based on cursor position, press the Set Zero selec
tor. The Set Zero pop up menu is displayed. See Figure 3 15.

Figure 3 15: The Set Zero Pop up Menu

To set the current horizontal value of Cursor 1 to zero, touch the Set Cur1
Zero selector. A D (delta) is displayed in the status area of the Cursor Type
selector, indicating that cursor measurements are made by subtracting that
value. This is useful in TDR and TDT measurements. Touch Clear Cursors
to return to normal mode. Touching Set Zero Rho enables you to position
the cursors on a portion of the trace that you wish to be used as the zero
rho" (or 50 W) position. (Set Zero Rho is not selectable unless Y Units is set
to Rho in the Graticules pop up menu.)
H To undo the effect of setting zero rho, the selected trace must be re
moved and redefined. However, you can also recalibrate the zero rho
point for better results.
Cursors
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