Tektronix CSA8000B - Manual (Page 180)

Creating Math Waveforms
3- 106 CSA8000B & TDS8000B User Manual
Overview Related control elements & resources To define a math waveform (cont.)
Select a math
waveform
3. Click the Math Waveform drop-down list in the dialog
box and select a one of the eight available math
waveforms, M1 through M8. Be sure to click to check
the On box, so that the waveform displays.
Tip. If the waveform you select already exists, its math
expression appears in the dialog box. You can still use
the waveform by clicking the Clear button, which
discards its previous math expression. Or repeat step 3
to select another waveform.
Build a math
expression
4. Use the dialog box at right to define a math expression.
See Table 3--8 on page 3--103 for expression examples;
some guidelines for creating your expression follow:
H Sources — C1 -- C8, R1 -- R8, and Meas1 --
Meas8 — should be set up before you use them
(references and automated measurement scalars
defined).
H Elements that appear grayed out cannot be
selected because they would result in an illegal
entry. For example, the sources are grayed out
because a source was just entered. You must enter
an operator before entering another source.
H Use the backspace button to remove the last entry;
use the clear key to remove the entire expression
and start over.
H Use parentheses to group terms in the expression
to control execution order, for example,
5*(C1 + C2).
Apply a filter 5. Use the filter controls in the dialog box to apply a filter to
the math waveform defined by the expression. Here are
some guidelines:
H Num Avgs. Set the number of averages applied by
the Avg( function. Only affect waveforms if the Avg(
function is used.
H Filter Risetime. Set to limit risetime to improve TDR
measurement results.
H Filter Mode. Choose Centered or Shifted for causal
or noncausal filtering.