Limit Testing
TDS 620A, 640A, & 644A User Manual
If you wish to create another limit test template, store it in another des-
tination to avoid overwriting the template you have just created.
If you wish to view the template you have created, press the MORE
button. Then press the button corresponding to the destination reference
memory you have used. The waveform appears on the display.
NOTE

To view the waveform data as well as the template envelope, it

might be useful to select the

Dots

display style (see

Display Modes

on page 3-28).

Limit Test Sources
Now specify the channel that will acquire the waveforms to be compared
against the template you have created.
1. Press SHIFT ACQUIRE MENU ➞ Limit Test Sources (main) ➞
Compare Ch1 to, Compare Ch2 to, Compare Ch3 to, Compare Ch4
to, Compare Math1 to, Compare Math2 to or Compare Math3 to
(side).
2. Once you have selected one of the four channels or a math waveform as
a waveform source from the side menu, press the same side menu button
to select one of the reference memories in which you have stored a
template.
Valid selections are any of the four reference waveforms Ref1 through
Ref4 or None. Choosing None turns limit testing off for the specified
channel.
NOTE

Specify the same reference memory you chose as the template

destination if you wish to use the template you just created.

If you have created more than one template, you can compare one
channel to one template and the other channel to another template.
Limit Test Setup
Now specify the action to take if waveform data exceeds the limits set by the
limit test template.
1. Press SHIFT ACQUIRE MENU ➞ Limit Test Setup (main) to bring up a
side menu of possible actions.
2. Ensure that the side button corresponding to the desired action reads
ON.