Agilent Technologies E1441A IMMediate, INTernal, EXTernal, TTLTRG<n>, For Gated Burst Mode

signal is required to start the waveform burst. The TRIGger:SOURce choices are:

IMMediate	Not available in Burst Modulation; specifying IMM
	actually selects EXTernal
INTernal	(the power-on/*RST default) This selects the internal
	trigger timer. The timer’s repetition rate is then set by
	the BM:INTernal:RATE command.
BUS	Burst can be triggered by a Group Execute Trigger
	(GET) IEEE-488.1 command or the *TRG IEEE-488.2
	common command.
EXTernal	This selects the "Ext Trig/FSK/Burst" connector as the
	source of the trigger signal.
TTLTRG<n>	Selects one of the 8 (TTLTRG0 through
	TTLTRG7)VXIbus TTL trigger lines as the trigger
	source.

For Gated Burst Mode

When the burst mode is "gated" (BM:SOUR EXTernal), the waveform burst is controlled (gated) by an an external trigger. The choices for TRIG:SOUR are:

EXTernal	Selects the "EXT Trig/FSK/Burst" connector as the
	source of the burst gating signal. Driven to a TTL
	"high", the waveform is output. When at a TTL "low",
	the output is at the DC offset voltage.
TTLTrg<n>	Selects one of the 8 (TTLTRG0 through
	TTLTRG7)VXIbus TTL trigger lines as the burst
	gating signal. When the TTLTRG line is true, the
	waveform is output. When the line is false, the output is
	at the DC offset voltage.
Bus, IMM,
and INT	These are not valid choices for gated burst mode.
	Specifying any of these selects EXTernal.

Use the following command to select a trigger source for burst modulation:

TRIGger:SOURce EXTernalBUSTTLTrg<0 - 7>

See “Triggering the Function Generator” on page 52. for more information

Burst Carrier Frequency The carrier frequency defines the repetition rate of the burst waveform in the triggered and external gated modes. In the triggered mode, the number of cycles specified by the burst count are output at the frequency of the carrier signal. In the external gated mode, the carrier frequency is output when the external gate signal is true (TTL high).

36 Agilent E1441A Application Information Chapter 2