User manual

3152B User Manual Publication No. 980935 Rev. M
3-34 Operation Astronics Test Systems
value must be at least 16 mV smaller than
the low level setting and must not be below
-16 V.
There are other parameters that control double pulses
, pulse
polarity, and others
. Refer to the programming section of this
manual for a complete listing of the digital pulse commands.
Pulse Design
Limitations
Since the 3152B creates pulses digitally, there are
inherent
limitations to these pulses:
1. Step size determines resolution and period.
The 3152B creates pulses digitally using a sample c
lock generator
that clocks memory points. The rate of the sample clock defines the
incremental resolution. For example, suppose you wish
to generate
pulses at a 100 ms pulse rate with 1
ms high time and the rest of
the period low. In this case, you could select a 1 kS/s or 10 kS/s
clock rate because this is fast enough to generate
a high signal of
1 ms using just 100 to 1,000 memory points. However, if
you
wanted to define much smaller pulse widths at larger pulse rates,
then the number of required points would
increase as a function of
the period. The limitation is set by the availability of waveform
memory.
2. Sum of pulse parameters cannot exceed the period.
The 3152B will automatically check to determine whether the
sum
of all timing components exceeds the
period. Always start your
pulse design by assigning the correct pulse period,
and then work
your way down the parameters list.
3. Only single-pulse and double-pulse trains can be designed.
The 3152B allows
generation of single or double pulse patterns
having fixed high and low amplitude values. If
you need to design
complex trains of pulse waveforms, you may do so
using the Pulse
Composer in ArbConnection. The pulse composer allows creation
of complex pulse trains with varying amplitude, shape,
and number
of pulses.
Generating Half
Cycle Waveforms
The Half-Cycle function is a special case of standard waveforms,
except that the waveforms are generated a half cycle at a time
and
displaced by a programmable
delay time. In continuous mode, the
half cycles are generated continuously. In triggered mode, one
half
at a time is generated only after a valid trigger event is received
.
There are three half-
cycle waveforms that can be generated: Sine,
Triangle, and Square. Use the commands below to select the half-
cycle function and program the parameters.
func:mod half Selects the half-
cycle function. If you have not
changed parameters, then the output will