Agilent Technologies DSO-X 4022A, User Manual

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Trigger Mode/Coupling
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Agilent InfiniiVision 4000 X-Series Oscilloscopes User's Guide 207
In either Auto or Normal trigger mode, a trigger may be missed if the
event occurs while the pre- trigger buffer is being filled. This may be more
likely, for example, when the horizontal scale knob is set to a slow
time/div setting, such as 500 ms/div.
Trigger Indicator The trigger indicator at the top right of the display shows whether triggers
are occurring.
In the
Auto
trigger mode, the trigger indicator can show:
• Auto? — the trigger condition is not found (after the pre- trigger buffer
has filled), and forced triggers and acquisitions are occurring.
•
Auto
— the trigger condition is found (or the pre- trigger buffer is being
filled).
In the
Normal
trigger mode, the trigger indicator can show:
• Trig'd? — the trigger condition is not found (after the pre- trigger buffer
has filled), and no acquisitions are occurring.
•
Trig'd
— trigger condition is found (or pre- trigger buffer is being filled).
When the oscilloscope is not running, the trigger indicator area shows
Stop .
When to Use Auto
Trigger Mode
The Auto trigger mode is appropriate when:
•
Checking DC signals or signals with unknown levels or activity.
• When trigger conditions occur often enough that forced triggers are
unnecessary.
When to Use
Normal Trigger
Mode
The Normal trigger mode is appropriate when:
• You only want to acquire specific events specified by the trigger
settings.
• Triggering on an infrequent signal from a serial bus (for example, I2C,
SPI, CAN, LIN, etc.) or another signal that arrives in bursts. The
Normal
trigger mode lets you stabilize the display by preventing the oscilloscope
from auto- triggering.
• Making single- shot acquisitions with the
[Single]
key.
Often with single- shot acquisitions, you must initiate some action in the
device under test, and you don't want the oscilloscope to auto- trigger
before that happens. Before initiating the action in the circuit, wait for
the trigger condition indicator
Trig'd? to display (this tells you the
pre- trigger buffer is filled).