Specifications

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Subject to change without notice
6 Trigger System
The trigger system of the HMO is
easy to handle by just observing
the HAMEG concept of instrument
operation.
Fig. 6.1: Front panel control area of
the trigger system
There are 4 keys destined for frequently used functions:
– TYPE: selects the type of trigger: SLOPE, PULSE, LOGIC,
VIDEO and the B-TRIGGER.
– SLOPE: selects the slope polarity.
– SOURCE: opens the menu for the selection of the trigger
source.
– FILTER: opens the menu for the selected trigger type in
order to select the exact trigger conditions.
Additional keys are provided for the selection of the trigger
modes: (AUTO. NORMAL, SINGLE).
6.1 TriggermodesAuto,Normal,Single
The basic trigger modes are directly selectable with the key
AUTO NORM. In AUTO mode the key will not be lit. If the key is
pushed it will light up red indicating NORMAL mode.
The oscilloscope always presents a signal in AUTO mode and
a signal will automatically yield a stable display if it fullls the
trigger conditions.
In NORMAL mode the signal will be displayed if it fullls the
trigger conditions, if it fails to do so the last stable triggered
display will remain on the screen.
If it is desired to record a signal which fullls the trigger con-
ditions only once, the key SINGLE must be pushed, it will light
up white. This indicates that the single trigger mode is active,
the RUN/STOP key will blink. The next return of the signal will
cause a single capture, the oscilloscope then goes into the STOP
mode, indicated by the RUN/STOP key lighting up in red.
6.2 Triggersources
Trigger sources are the 4 analog channels and the external
trigger input. If the optional logic probe HO3508 with 8 or 16
logic channels is connected, also those up to 16 digital chan-
nels can serve as trigger sources.
6.3 Slopetrigger
The simplest and most used trigger type is slope trigger, this
one is also selected in the AUTOSETUP function. Pushing the
AUTOSETUP key will hence change any previously selected
trigger type to slope trigger. For the selection of the trigger
type push the key TYPE in the trigger control section of the front
panel. A menu will open and offer the options. If the type SLOPE
was not selected (blue background) pushing the respective soft
key will change to slope. The SLOPE key is also used to step
through the options rising, falling, or both slopes. In the center
of the status line top center above the graticule the type selected
will be shown. If the key FILTER is pushed, the respective menu
will open and offer the available options.
Here the trigger signal coupling can be selected:
DC: The trigger signal is used with its dc content.
AC: The trigger signal is routed via a 5 Hz high pass lter.
HF: The trigger signal is routed via a 15 kHz high pass lter.
The trigger level is no longer adjustable. This mode
should only be used with very high frequency signals.
LOW PASS: The trigger signal is routed via a 5 kHz low pass
lter.
NOISE RED.: The trigger signal is routed via a 100 MHz low
pass lter removing higher frequency interference.
The coupling modes low pass and noise reduction can not be
simultaneously selected, but they can be used with DC or AC
coupling.
Fig. 6.3: The type B-Trigger
The slope trigger can be coupled with a so called „B Trigger“.
This option is available after pushing TYPE. This function allows
Fig. 6.2: Coupling modes with slope trigger
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Trigger System