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7.1 Noun Explanation of Trigger System
(1) Trigger Source
A signal for generating a trigger. Trigger can be obtained from a variety of information sources, such
as input channel (CH1, CH2), external trigger (EXT), mains electricity, etc.
a. Input channel: Select any one of the analog signal input port CH1~CH2 on the front panel of the
oscilloscope as a trigger signal. Trigger level range:
±
5 grids from screen center.
b. External trigger: Select the input signal EXT TRIG (EXT input port) on the front of the
oscilloscope as a trigger signal. For example, the external clock input to EXT Trig port to be a
trigger source. EXT signal trigger level within the range from
–
4 V~ +4 V can be set.
c.
Mains electricity
：
Used to observe the related signal of mains electricity, such as the relation of
lighting equipment and power supply equipment, to obtain stable synchronization.
(2) Trigger Mode
Trigger mode determines the behavior of the wave during a trigger event. This oscilloscope provides
three kinds of trigger modes: auto, normal, and single.
a. Auto trigger
：
When there is no trigger signal, the system automatically collect and display data.
When the trigger signal is generated, it automatically switch to trigger scanning, so that the
signal will be synchronized.
Auto trigger mode is suitable for
Check DC signal or signal with unknown electrical feature
Note:
This mode allows 50 ms/div or in slower timebase scale to set no trigger signal in ROLL mode.
b. Normal trigger: The oscilloscope can only collect data when the trigger condition is satisfied.
When there is no trigger signal, the oscilloscope will stop collect data. When the trigger condition
is satisfied, refresh the current waveform data display on the screen, otherwise, it remains the
last triggered waveform.
Normal trigger mode is suitable for
Only collect the specific event appointed by the trigger setting;
Rare trigger event, use normal mode can prevent the oscilloscope from automatic trigger, so that
the waveform can be stable display.
c.
Single trigger: Delete the waveform display on the screen, the oscilloscope waits for the trigger.
When the instrument detects a single trigger, the waveform will be sampled and displayed, and
then the instrument enters the STOP state.
Single trigger mode is suitable for
Capture casual event or aperiodicity signal, such as up, down waveform;
Rare trigger event
(3) Trigger Coupling
Trigger coupling determines which part of the signal will be transmitted to the trigger circuit. The
coupling type includes DC, AC, low frequency/high frequency suppression and noise suppression.
a. DC
：
Let all the components of the signal pass through
