Keithley 2303, User Manual

Page: 53 / 152

Pulse Current Measurements 3-9
Pulse current digitization
The following discussion explains how to digitize a current waveform. A programming
example at the end of this section demonstrates proper command sequence for pulse current
digitization.
With pulse current digitization selected, readings are taken at a constant integration time of
33µsec across the pulse or pulse train. The message “DIGITIZE” is displayed instead of read-
ings. Pulse current digitization is selected by disabling trigger synchronization:
SENS:PCUR:SYNC <b>
<b> = OFF Select pulse current digitization (trigger synchronization disabled).
= ON Select pulse current measurements (trigger synchronization enabled).
The commands to set the trigger level and trigger delay for pulse current measurements also
apply for pulse current digitization. However the trigger delay can be set up to five seconds.
SENS:PCUR:SYNC:DEL <NRf>
<NRf> = 0 to 5 Trigger digitization delay in seconds (10µsec steps).
Note that the “NO PULSE” message will be displayed if the pulse is not detected.
When the pulse is detected, the digitization process syncs up to the edge specified by the
following command:
SENS:PCUR:MODE <name>
<name> = HIGH or AVER Sync up to rising edge of pulse.
= LOW Sync up to falling edge of pulse.
After any specified delay period expires, the instrument takes the number of readings
specified by the average count command:
SENS:PCUR:AVER <NRf>
<NRf> = 1 to 5000 Digitize 1 to 5000 readings.
NOTE Although the integration time is 33µsec, some processing time is needed between
readings. The time between readings, including integration and processing time, is
about 278µsec.