Start Trigger

A Start trigger initiates signal generation. When a Start trigger is received, the RF output signal begins to generate as shown in the following figure. Received triggers are ignored until the niRFSG Initiate VI or the niRFSG_Initiate function is called. A Start trigger received after signal generation has started is ignored. The following figure illustrates an NI-RFSG Start trigger model.

the NI RF signal generator Start trigger is controlled by the AWG module. Configure the Start trigger using the Start Trigger Type property or the NIRFSG_ATTR_START_TRIGGER_TYPE attribute.

Note  The NI 5610 upconverter module adds an additional delay, typically 1200 ns, to the delay from the Start trigger to waveform generation that is specified for stand-alone use of the AWG module.

Start Trigger Types

The following three types are available for the NI RF signal generator Start trigger:

• None—Signal generation starts immediately upon execution of the niRFSG Initiate VI or the niRFSG_Initiate function. No Start trigger is necessary. This configuration is the default in NI-RFSG.
• Software—After initiation, signal generation does not begin until a software Start trigger is received. Call the niRFSG Send Software Edge Trigger VI or the niRFSG_SendSoftwareEdgeTrigger function to send the software Start trigger.
• Digital Edge—After initiation, signal generation does not begin until a digital edge is received. Specify the digital edge source by using the Digital Edge Start Trigger Source property or the NIRFSG_ATTR_DIGITAL_EDGE_START_TRIGGER_SOURCE attribute.

Tip  Sending a software trigger when the Start Trigger Type property or the NIRFSG_ATTR_START_TRIGGER_TYPE attribute is set to Digital Edge or NIRFSG_VAL_DIGITAL_EDGE, respectively, also starts signal generation. You can use this to create a software timeout to avoid leaving the instrument in a waiting state if the digital edge is never received.

The following figure depicts the possible software trigger sources for the AWG module.

Note  Refer to the NI RF Signal Generators Getting Started Guide for more information about AWG modules and triggering.