Tektronix DPO2304SX, Печатная инструкция

Страница: 654 / 920

Advanced triggering
You can check the advanced trigger status in the readout. The readout indicates the trigger type and then shows sources, levels,
or any other parameters that are important for the particular trigger type.
Set up triggering from the trigger setup window
The following trigger parameters are accessible only through the Trigger control windows:
■ Holdoff
■ Trigger level presets
■ Force trigger
Use the procedures below to set up these trigger parameters.
Set the trigger holdoff. Changing the holdoff time helps to stabilize triggering.
1. Push the front-panel Advanced button.
2. In the Trigger control window, select the Mode tab.
3. Click Default or Time:
■
Auto. Uses the instrument default holdoff time, which is five times the current horizontal scale setting. Default maintains
a good value for general-purpose triggering.
■
Time. Enables you to enter a holdoff that may allow more stable triggering. This time is used at all horizontal scale
settings
4. If using Time, click in the Trig Holdoff entry box and use the multipurpose knob to enter a time value. The holdoff range is
250 ns to 100 s.
Select a preset trigger.
1. Push the front-panel Advanced button.
2. In the Trigger control window, select the A Event tab.
3. 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 within the trigger graphic, along with the other trigger type setup controls.
4. Click Level, and then click the keypad icon to open the keypad. Click on either TTL, ECL, or USER:
■
TTL. Sets the trigger level to +1.4 V.
■
ECL. Sets the trigger level to –1.3 V.
■
USER. You can set the trigger level to a preset voltage.
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.
Trigger graphic
The trigger graphic displays a visual indicator of the trigger criteria. Depending on the trigger type, the instrument will update the
graphic as you define the trigger parameters.
How to ?
622 DPO70000SX, MSO/DPO70000DX, MSO/DPO70000C, DPO7000C, and MSO/DPO5000B Series