Rigol DS1000C User Manual page 86

RIGOL
Trigger Key points
1. Trigger Source:
Trigger can occur from several sources: Input channels (CH1, CH2 and D15-D0
on mixed signal oscilloscopes), AC Line, Ext, Ext/5.
CH1 or CH2:
work when selected as a trigger source whatever displayed or not.
Ext Trig: The instrument can trigger from a third source while acquiring
data from CH1 and CH2. For example, you might want to trigger from an
external clock or with a signal from another part of the test circuit. The Ext, Ext/
5 trigger sources use the external trigger signal connected to the EXT TRIG
connector. Ext uses the signal directly; it has a trigger level range of +1.6 V to
-1.6 V. The EXT/ 5 trigger source attenuates the signal by 5X, which extends the
trigger level range to +8 V to -8 V. This allows the oscilloscope to trigger on a
larger signal.
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 power cord, so you do not have to input an AC
trigger signal. 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
2-56
It is the most commonly used trigger source. The channel will
© Copyright RIGOL Technologies, Inc. 2007.
User's Guide for DS1000 Series