for exactly the same reasons as described in the Pulse Setup section; refer to that section for a
detailed explanation.
Pressing
next
calls the pulse delay screen for the first pulse:
◊
Pulse 1 delay
♦
p0·000 ns
(0·000 ns)
◊
done next
◊
The pulse delay is entered in the same way as pulse width and, again, the
actual
delay is
shown below the
program
delay for the same reasons. The delay value that can be entered
must be in the range ± (pulse-train period -1 point); positive values delay the pulse with respect to
waveform sync from SYNC OUT; negative values cause the pulse to be output before the
waveform sync.
Pressing
next
on this screen calls the first of the 3 screens for setting the parameters of Pulse
2, and so on through all the pulses in the pulse-train. In this way all parameters of all pulses are
set. The pulse-train is built when
next
is pressed on the last screen of the last pulse or if
done
is pressed on any screen.
Care must be taken that the set widths and delays of the individual pulses are compatible with
each other and the overall pulse-train period, i.e. delays must not be such that pulses overlap
each other and widths must not exceed the pulse-train period; unpredictable results will
occur if these rules are not followed.
Once the pulse-train has been defined the period can be adjusted irrespective of the pulse width
and delay settings for the individual pulses because, unlike a conventional pulse generator, the
individual pulse widths and delays are adjusted
proportionally
to the period as the period is
changed.
Period can also be changed from the
PULSE-TRN PERIOD
screen called by pressing the FREQ
key with pulse-train mode selected:
PULSE-TRN PERIOD
100·0 us
◊
freq period
♦
The new setting can be entered either as a period in the way already described or as a frequency
by first pressing the
freq
soft-key. However, changing the period/frequency from this screen is
slightly different from changing period on the
pulse-train setup
screen. When changing
from this screen the number of points in the waveform is never changed (just as with a true arb)
which means that the shortest period/highest frequency that can be set is the number of
waveform points x 33·33ns. To achieve faster frequencies (up to the specification limit) the period
must be changed from the pulse setup screen; changing the frequency from this screen causes
the number of points to be reduced as the period is reduced (for period <1·67ms).
Waveform Hold in Pulse and Pulse-Train Modes
A logic low or switch closure at the rear panel HOLD IN socket stops the waveform at the current
level; a logic high or switch opening restarts the waveform from that level.
If, while the waveform is held, a logic high is applied to TRIG IN (regardless of the TRIG IN setup)
then the waveform is reset to its first point; the waveform will restart from this point when a high is
applied to the rear panel HOLD IN socket.
53