RIGOL DS1000D - Manual (Page 81)

RIGOL
© 2008 RIGOL Technologies, Inc.
User’s Guide for DS1000E, DS1000D Series
2-51
Trigger Key points
1. Trigger Source: Trigger can occur from several sources: Input channels (CH1
and CH2), AC Line, Ext.
 CH1 or CH2: It is the most commonly used trigger source. The channel works
when selected as a trigger source whatever displayed or not.
 Ext Trig: The instrument can be triggered from a third source while acquiring
data from CH1 and CH2. For example, to trigger from an external clock or with
a signal from another part of the test circuit. The Ext trigger sources use an
external trigger signal connected to the EXT TRIG connector. Ext uses the signal
directly; it has a trigger level range of -1.2V to +1.2V.
 AC Line: AC power can be used to display signals related to the power line
frequency, such as lighting equipment and power supply devices. The
oscilloscope gets triggered on its AC power input; an AC trigger signal is not
required. When AC Line is selected as trigger source, the oscilloscope
automatically set coupling to DC, set trigger level to 0V.
2. Sweep Mode: The sweep mode determines how the oscilloscope behaves in
the absence of a trigger event. The oscilloscope provides three trigger modes:
Auto, Normal, and Single.
 Auto: This sweep mode allows the oscilloscope to acquire waveforms even
when it does not detect a trigger condition. If no trigger condition occurs while
the oscilloscope is waiting for a specific period (as determined by the time-base
setting), it will force itself to trigger.
When forcing invalid triggers, the oscilloscope cannot synchronize the
waveform, and the waveform seems to roll across the display. If valid triggers
occur, the display becomes stable on the screen.
Any factor results in the un-stability of waveforms can be detected by Auto
Trigger, such as the output of Power supply.
NOTE: When horizontal control is set under 50 ms/div, Auto mode allows the
oscilloscope not to capture trigger signal.
 Normal: The Normal mode allows the oscilloscope to acquire a waveform only
when it is triggered. If no trigger occurs, the oscilloscope keeps waiting, and the