User`s manual

External Stop
Trigger Slope
An external stop trigger signal is applied to the AFG’s “Stop Trig/FSK/Gate
In” BNC connector. The edge of the signal on which the AFG is triggered is
set with the
TRIGger:STOP:SLOPe command. The edges are:
• POSitive – Selects the rising edge of the signal.
• NEGative – Selects the falling edge of the signal.
AFG Gating
Sources
The source which gates the triggers is specified with the
TRIGger[:STARt]:GATE:SOURce command. The available sources are:
• EXTernal – The Agilent E1445A’s front panel “Stop Trig/FSK/Gate
In” BNC connector (default source). This BNC is driven by TTL
levels.
• TTLTrg0 through TTLTrg7 – The VXIbus TTL trigger lines.
AFG Gate Polarity The polarity of the signal which gates the output is specified with the
TRIGger[:STARt]:GATE:POLarity command. The polarities which can be
selected are:
• NORMal – Selects an “active high” gate. When the gate signal is
high, the gate is active and the output is suspended at the last
amplitude point triggered. When the gate is low (inactive), the
output resumes with the next point.
• INVerted – Selects an “active low” gate (default polarity). When the
gate signal is low, the gate is active and the output is suspended at
the last amplitude point triggered. When the gate is high (inactive),
the output resumes with the next point.
The gate polarity applies only to the EXTernal gate source (front panel
“Gate In” BNC). If you are using a TTLTrg0 through TTLTrg7 trigger line
as a gating source, the gate is always “active low”.
Gating and
Signal Phase
Gating the triggers suspends the output at the last amplitude point triggered.
When the gate is inactive, the waveform resumes with the next amplitude
point. Thus, the phase of the signal remains continuous.
Enabling the Gate Before the AFG triggers can be gated, the gate must be enabled. This is
done with the
TRIGger[:STARt]:GATE:STATe command. When the mode is
ON, gating is enabled. When OFF, gating is disabled.
200 Arming and Triggering Chapter 5