
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 SETUP
screen on which the burst count
is set. The other trigger parameters are set on the
TRIGGER INPUT SETUP
screen called by
pressing the TRIG IN key.
Trigger Source
The trigger source can be selected with the
source
soft-key on the
TRIGGER INPUT SETUP
screen to be
internal, external,
or
manual.
With
internal
selected the internal trigger generator is used to initiate a burst; with
external
selected the specified edge of the signal at TRIG IN is used to initiate a burst. With
either
internal
or
external
selected burst can
also
be initiated by pressing the MAN/SYNC
key or by remote command; with
manual
selected as the source,
only
the MAN/SYNC key or
remote command can be used to initiate a burst.
Trigger Edge
The
slope
soft-key is used to select the edge (
positive
or
negative
) of the external
trigger signal that is used to initiate a burst. Note that the
trigger
signal from SYNC OUT,
used for synchronising the display of triggered burst on an oscilloscope for example, is always
positive-going at the start of the burst.
Burst Count
The number of complete cycles in each burst following the trigger is set from the
TRIGGER
SETUP
screen called by pressing
setup
on the
MODE
screen.
TRIGGER SETUP:
◊
burst cnt: 0000001
clk: waveform sync
done
◊
The required count can be set by pressing the
burst cnt
soft-key followed by direct entries
from the keyboard or by using the rotary control. The maximum number of clocks that can be
counted is 1048575 (20
20
-1).
The source of the burst count is selected by the
clk
soft-key on the
TRIGGER SETUP
screen.
The default setting is
waveform sync
which is output once per cycle for all waveforms; with
this setting, counting
waveform sync
is the same as counting waveform cycles so
burst
cnt
sets the number of cycles. The first cycle starts, and the last cycle stops, at the first point in
the waveform. Alternatively, for arbitrary waveforms,
clk
can be set to
pos’n marker
and
the burst count will then be of position marker(s) set in the arbitrary waveform, see
edit
waveform
menu on the
MODIFY
screen. The waveform starts at the first point and stops at the
n
th
marker where n is the burst count; at the next trigger the waveform playback starts at the n
th
marker and stops at the 2n
th
marker, and so on. The marker count wraps-round to the start of the
waveform and counts through the markers again so that the waveform burst is every n markers,
regardless of how many markers are in each waveform.
31