Pulse Phase - Keithley 2520 User Manual

8-4 Triggering

Pulse phase

During the pulse phase, the unit outputs one current pulse with the programmed pulse
width (set to between 500ns and 5ms with the PW key). If the unit is in the fixed (non-
sweep mode), the pulse amplitude is the same for each cycle through the loop. However, if
the unit is in the sweep mode, the pulse amplitude is set to the programmed value for that
sweep point. 10MHz samples are taken during the pulse phase, and one set of voltage and
current readings is DSP processed for each pulse.
Filtering
If the filter is enabled, the instrument cycles through the delay-pulse loop for the pro-
grammed filter count and averages the specified number of readings to yield a single set of
filtered readings (measurements).
Sweep points
When a sweep is enabled, the unit cycles through the complete delay-pulse process
(including filtering if enabled) for the programmed number of sweep points. For linear
staircase sweeps, the number of points depends on the start, stop, and step current values.
For log staircase sweeps, the number of points depends on the start and stop current values
and the programmed number of points.
Counter
The programmable counter is used to repeat operations within the Trigger Layer. For
example, to repeat a sweep three times, the trigger counter would be set to 3. If the sweep
has a total of 10 points, a total of 30 measurements will be made.
The maximum finite trigger counter value is 5000. However, the product of the trigger
count and the number of sweep points cannot exceed 5000.
Output trigger
The Model 2520 can be programmed to output a trigger (via rear panel Trigger Link con-
nector) after various trigger model operations. An output trigger is used to trigger another
instrument to perform an operation. See
When enabled, the unit outputs a trigger when operation leaves the Trigger Layer and
enters back into the Idle Layer. This output trigger is typically sent to another instrument
to signal the end of a sweep.
"Trigger link," page 8-5, for more information.
Model 2520 User's Manual