DPO6000
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MPO6000 Series Digital Phosphor Oscilloscope Instruction V1.1
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6.Trigger System
Trigger can be understood as an event (or action);For example, when taking a photo, the
action of pressing the shutter is the trigger, which is an event that starts the camera to
record the image. For oscilloscopes, when the trigger condition is established, the
waveform (sampled data) will be recorded and displayed on the screen. For digital
oscilloscope, it samples waveform continuously no matter whether it is stably triggered,
but only stable trigger can ensure stable display. The trigger module ensures that every
time base sweep or acquisition starts from the user-defined trigger condition, namely
every sweep is synchronous to the acquisition and the waveform acquired overlap to
display stable waveform.Trigger setting should be based on the features of the input
signal, thus you need to have some knowledge of the signal under test to quickly capture
the desired waveform. This oscilloscope provides abundant trigger types,which can help
you to focus on the desired waveform details.
The trigger determines when the oscilloscope begins to acquire data and display
waveform.Once the trigger is set up correctly, an oscilloscope can convert an unstable
display or blank screen into a meaningful waveform.Here are some basic concepts of the
trigger.
6.1.Trigger Source
Press signal source in the trigger control area of the front panel(Trig Menu) to select the
desired trigger source. Analog channels CH1-CH4, digital channels D1.0-D1.3,D2.0-D2.3,
D3.0-D3.3,D4.0-D4.3 can all be used as trigger source.
Analog channel input
:
Signals input from analog channels CH1-CH4 can all be used as trigger source. If the
trigger source channel selected isn’t enabled,this trigger is regarded as invalid trigger.
Digital channel input
:
Only the digital channels connected to oscilloscopes can be used as trigger source(some
trigger types can’t be selected,such as slope trigger).
6.2.oscilloscope acquisition process
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.
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).After finding the trigger, the oscilloscope is collected and stored in the
post-trigger storage area.
6.3.Trigger Mode
Auto Mode
Performs the acquisition freely in absence of valid trigger. It allows the
generation of untriggered waveform with the time base set to 100ms/div or slower.When a
oscilloscope detects the valid trigger condition,it will complete a valid trigger acquisition.
When a oscilloscope doesn’t detect the valid trigger condition,it will complete a acquisition
without trigger.
