LeCroy’s ArbStudio Arbitrary Waveform Generator includes features to both generate triggers synchronous with output waveforms and to accept external triggers to initiate waveforms or waveform segments. This application brief addresses both of these features.
Generating an internal trigger. Connect the ArbStudio generator to the computer running the ArbStudio software. Turn on both devices and start the ArbStudio software. Open a new workspace. Configure ArbStudio to be an Arbitrary Waveform Generator.
After ArbStudio starts open the channel 1 settings window. Select the Run Mode Tab and set the Run Mode to Continuous as shown in Figure 1.
Select the Trigger Out Tab. Click on Marker in Channel Events and select the desired polarity as shown in Figure 2. Press OK. This setting will use the user set marker for a waveform to be used as the output trigger.
Click on the Setup Device Icon (outlined in Yellow in Figure 3). Select the Trigger Out Math tab of the Setup Device pop up. This determines the logic applied to the trigger outputs of both channels. Set the Trigger out logic to OR. Press OK . This will allow either channel to output a trigger pulse.
Open the Waveform Sequencer and create the desired waveform(s). After the desired waveform(s) are complete as shown in Figure 4, double click on the waveform entry you want to associate the output trigger with. This will open the Waveform Editor. In figure 4 the highlighted selection, Waveform 1, will be used.
In the upper left hand corner of the Waveform Editor is the Waveform Manager. Click on Waveform1, it will be highlighted in blue.
The Marker list in the lower left hand corner will be change from being ‘grayed out’ to being active.
Click on the green plus sign to add a marker to the list. Note that a vertical green line will appear on the waveform graphic display. This green line is the marker. You can click on the line using your mouse and drag it anywhere on the waveform. This will be the point at which the output trigger will be generated.
Click OK to exit the Waveform editor and return the Waveform Sequencer. If you haven’t already loaded the waveform into the sequencer, do so now using the arrow icon in the sequencer. Press the Run button on the upper tool bar. The waveform and trigger will now be output from the ArbStudio hardware as shown in figure 6.
You can generate multiple markers or add additional marker to other waveforms to create multiple output trigger instances.
Using the ArbStudio Input Trigger
The ArbStudio input trigger can be enabled to be a ‘Force Trigger’ event. The effect of the input trigger depends on the Run Mode that the operator selects in the channel settings pop up menu under the Run Mode tab as shown in Figure 7.
The run modes characteristics are as follows:
|Single||After the Force Trigger command the Sequencer list is generated from the first waveform to the last. The last waveform is repeated continuously until a Force Stop command.|
|Continuous||After the Force Trigger command the sequencer list is generated from the first waveform to the last and loops back to the first continuously until a Force Stop command.|
|Stepped||After the Force Trigger the first waveform on the sequencer list is generated. The last sample of this waveform is kept until the next Force Trigger command starts the generation of the second waveform and so on. If the Force Trigger is received while the waveform is being generated the command acts after the generation of its last sample. The generation ends with the Force Stop command.|
|Burst||After the Force Trigger the first waveform on the sequencer list is generated until the next Force Trigger commands starts the second waveform and so on. Once the sequencer list is exhausted the generation returns to the first waveform in c cyclic way. If the Force Trigger is received while the waveform is being generated the command acts after the generation of its last sample. The generation ends with the Force Stop command.|
To enable the input trigger double click on the Settings selection in the channel 1 Device Control field. This will display the Settings Ch 1 pop up. Select the Trigger In tab and click on the Trigger In Enabled button. Select the Source connector, the desired edge polarity for the trigger, and the trigger Action as shown in Figure 8.
The trigger input should be applied to the selected input connector. In this example we chose the input connector to be the front panel Trigger Input bnc connector (see Figure 8).
The specification for the Trigger Input signal level is a level change from below 0.8 V to above 2 V. The maximum input specifications for the Trigger Input is < 4 V so the input should be between 2V and < 4V.
In this application brief we have investigated ArbStudio’s provisions for outputting triggers synchronous with the output waveforms and accepting external triggers to begin waveform generation.