User`s guide

178 Agilent X-Series Signal Generators User’s Guide

Basic Digital Operation (Option 653/655/656/657)

Triggering a Waveform

Figure 8-7 Triggering Softkeys

Triggers control data transmission by controlling when the signal generator transmits the modulating

signal. You can configure trigger settings so that data transmission occurs once (Single mode),

continuously (Continuous mode), or starts and stops repeatedly (Gated and Segment Advance modes).

A trigger signal contains both positive and negative states; you can use either for triggering.

When you initially select a trigger mode or when you change from one triggering mode to another,

you may lose the carrier signal at the RF output until the modulating signal is triggered. This is

because the signal generator sets the I and Q signals to zero volts prior to the first trigger event. To

maintain the carrier signal at the RF output, create a data pattern with the initial I and Q voltages

set to values other than zero.

When you initially turn the Arb ON or select a trigger mode or when you change from one triggering

mode to another, you may temporarily lose the carrier signal for a few tens of milliseconds at the RF

output. The Arb will present the idle IQrms value of the next Arb waveform to the IQ modulator.

This ensures that the RF carrier output is at the correct amplitude level while the Arb waits for a

trigger. When that trigger is received, the Arb begins playing the waveform and the modulated RF

carrier exhibits no undesirable transients.

There are two parts to configuring a waveform trigger:

• Type determines the behavior of the waveform when it plays (see Trigger Type on page 179).

• Source determines how the signal generator receives the trigger that starts the modulating

waveform playing (see Trigger Source on page 180).

Mode > Dual ARB

page 179

page 180

For details on each key, use key help

as described on page 44.