External Trigger Input; Adjacent Channel Trigger Output; Triggered Burst - Fluke 281 User Manual

External Trigger Input

External trigger or gate signals are applied to the front panel TRIG IN socket which has a
TTL level (+1·5 V) threshold. In triggered burst mode the input is edge sensitive; the
selected edge of each external trigger initiates the specified burst. In gated mode the input
is level sensitive; the output of the main generator is on whilst the gate signal is true.
The minimum pulse width that can be used with TRIG IN in triggered burst and gated
mode is 50 ns and the maximum repetition rate is 1 MHz. The maximum signal level that
can be applied without damage is ±10 V.
When triggered burst or gated modes are selected the SYNC OUT source automatically
defaults to trigger which is always a positive-edged version of the external trigger
or gate signal when external triggering or gating is specified.

Adjacent Channel Trigger Output

On multi-channel instruments the trigger out signal of an adjacent channel can be used as
the control signal for a triggered burst. The channel numbering 'wraps round' such that
channel 1 follows channel 4.
The source of the trigger out signal is selected by the source soft-key on the
TRIGGER OUT screen called by the TRIG OUT key.
The source choices are as follows:
wfm end:
pos'n marker:
seq sync:
burst done:
The default choice is wfm end except when the channel is running a sequence in
which case it becomes seq sync. To set the trigger out to anything other than its
default it is necessary to change the mode from auto to manual using the mode
soft-key.
Trigger out is an internal signal but, as with the other trigger sources, a positive-edged
version is available at the triggered channel's SYNC OUT with its default source of
trigger selected.

Triggered Burst

Triggered burst mode is turned on with the triggered soft-key on the MODE
screen. The setup... soft-key on this screen accesses the TRIGGER/GATE SETUP
TRIGGER OUT:
mode: auto
source: wfm end
Waveform end; a positive-going pulse coincident with the end
of a waveform cycle (and the start of the next).
Position marker; arbitrary waveforms only. Any point(s) on
the main waveform may have marker bit(s) set high or low.
No output if selected for a standard waveform.
Sequence sync; a positive-going pulse coincident with the end
of a waveform sequence.
A positive-going pulse coincident with the end of the last
cycle of a burst.
Triggered Burst and Gate

Triggered Burst

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