Chapter 5 To Trigger the Oscilloscope    RIGOL 
DS2000E User’s Guide     5-3 
Trigger Mode 
 
The following is the schematic diagram of the acquisition memory. To easily 
understand the trigger event, the acquisition memory is divided into the pre-trigger 
buffer and post-trigger buffer. 
 
Figure 5-1 Schematic Diagram of the Acquisition Memory 
 
After the system runs, the oscilloscope operates by first filling the pre-trigger buffer. 
It starts searching for a trigger after the pre-trigger buffer is filled. While searching 
for the trigger, the data sampled will still be transmitted to the pre-trigger buffer (the 
new data will continuously overwrite the previous date). When a trigger is found, the 
pre-trigger buffer contains the data acquired just before the trigger. Then, the 
oscilloscope will fill the post-trigger buffer and display the data in the acquisition 
memory. If the acquisition is activated via RUN/STOP, the oscilloscope will repeat 
this process; if the acquisition is activated via SINGLE, the oscilloscope will stop 
after finishing a single acquisition (you can pan and zoom the waveform currently 
displayed). 
 
Press MODE in the trigger control area (TRIGGER) on the front panel or press 
MENU  Sweep to select the desired trigger mode. The corresponding status light 
of the mode currently selected turns on.  
 
Auto: 
In this trigger mode, the oscilloscope will trigger and sample to display the 
waveforms forcibly if no specified trigger condition is found.  
This trigger mode is applicable to the following conditions: the signal level is 
unknown; the DC should be displayed; the trigger condition always occurs; forcible 
trigger is not required.  
Pre-trigger Buffer 
Post-trigger Buffer 
Trigger Event 
Acquisition memory