Once the segment to be edited has been set the waveform for that segment is selected with the
wfm
(waveform) soft-key; the list of all arbitrary waveforms already created is stepped through
with repeated presses of the
wfm
soft-key or by using the rotary control. The part of the
waveform that will be used is defined by the limits setting (default setting is the whole waveform)
as described in the Waveform Limits paragraph of the Modifying Arbitrary Waveforms section. For
convenience the
Limits
screen can be directly accessed from sequence set-up by pressing the
limit
soft-key; pressing
done
after setting limits will return the display to the sequence set-up
screen.
The criteria for stepping between waveform segments is set by the
step on
soft-key. The
default setting is
step on: count
which means that the waveform will step on to the next
segment after the number of waveform cycles specified in the
cnt
(count) field; up to 32768
cycles can be set with
cnt
selected, using direct keyboard entries or by rotary control.
Alternatively, the step on criteria can be set to
trig edge
or
trig level
in the step on field;
trigger edge
or
trigger level can be mixed with count (i.e. some segments can step on count,
others on the specified trigger condition) but trigger edge cannot be mixed with trigger level in the
same sequence.
If
trig edge
is selected the sequence starts running at the first waveform segment when
sequence is set to
run
and steps to the following segments in turn at each subsequent trigger.
The trigger source can be any of the settings selected on the
TRIGGER INPUT SETUP
screen
(called by the TRIG IN key); these are described fully in the Triggered Burst and Gate section. At
each trigger the current waveform cycle plus one further whole cycle are completed before the
waveform of the next segment is started.
If
trig level
is selected the sequence runs continuously through each segment in turn (1
cycle per segment) while the trigger level is true. When the trigger level goes false the waveform
currently selected runs continuously until the level goes true again at which point the sequence
runs continuously through each segment in turn again. The trigger level source can be any of the
settings selected on the
TRIGGER INPUT SETUP
screen with the exception of the MAN/SYNC
key which can only produce an edge, not a level, when pressed.
Providing the
step on:
field is set to
count
for all segments the waveform sequence can also
be run in Gated and Triggered Burst modes in the same way as simple waveforms; refer to the
Triggered Burst and Gated section for full details.
Note that in Triggered Burst mode the clock source should be set to
waveform sync
on the
TRIGGER SETUP
screen and will actually count
sequence sync
when sequence mode is
running. The burst counter therefore counts complete sequences (up to 1048575); this is in
addition to the counts of up to 32768 cycles in each waveform segment.
The individual segments of the sequence can be turned on or off with the
on-off
soft-key. Note
that turning a segment off will automatically set all subsequent segments off; turning a segment
on will turn on that segment and any others between segment 1 and itself that were previously
off. Segment 1 is always on.
When the whole sequence is defined the set-up is constructed by pressing the
done
soft-key
which returns the display to the initial
SEQUENCE
screen. The sequence can be run and stopped
from this screen with the
run
and
stop
soft-keys respectively.
Frequency and Amplitude Control with Arbitrary Waveforms
Frequency and Amplitude control work in essentially the same way as for standard waveforms
with the following minor differences.
Frequency
Pressing the FREQuency key with an arbitrary waveform selected calls the
ARBITRARY
FREQUENCY
screen:
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