305
7. Click a Trigger Type button to select a trigger, such as
Edge, that uses a level adjustment. A trigger uses a level
adjustment if the Level control appears on the right side of
the screen with the trigger type setup controls.
8. Click Level, and then click the keypad icon to open the
keypad. Click on either TTL, ECL, or USER:
 TTL fixes the trigger level at +1.4 V.
 ECL fixes the trigger level at –1.3 V.
 USER fixes the trigger level at a user preset voltage (see
Steps 9 through 12).
When you set the volts/div less than 200 mV, the instrument
reduces the TTL or ECL trigger levels below standard TTL and
ECL levels. This reduction occurs because the trigger level range
is fixed at +12 divisions from the center. At 100 mV (the next
lower setting after 200 mV) the trigger range is +1.2 V, which is
less than the typical TTL (+1.4 V) or ECL (–1.3 V) level.
Define new trigger level
presets
9. If the menu bar is not displayed, click the Menu toolbar
button.
10. Select the Utilities menu User Preferences option. The User
Preferences control window opens.
11. Select the Keypad Defaults tab.
12. Click the appropriate Trig Level and adjust the preset using
the multipurpose knob or pop-up keypad.
13. If desired, click a Keypad Label and change the label of
the preset using the pop-up keypad.
Force a trigger
14. Push the front-panel ADVANCED button.
15. On the Trigger Setup control window, select the A Event or
B Event tab
16. Click Edge.
17. To force the instrument to immediately acquire one
waveform record, even without a trigger event, click Force
Trigger.
Forcing a trigger is useful when, in normal trigger mode, the
input signal is not supplying a valid trigger. Click Force
Trigger to quickly confirm that there is a signal present for
the instrument to acquire. Then determine how to trigger on
the signal (for example, push LEVEL to set 50%, check the
trigger source setting, and so on).
To Next Page
Loading...
Need help?
General
