Stanford Research Systems SR780, Руководство по эксплуатации и программированию

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4-86 Trigger Menu
SR780 Network Signal Analyzer
For octave and swept sine measurements, the first trigger after arming starts the
measurement and subsequent triggers are ignored. Use [Start/Reset] to reset the
measurement and start again.
The Trigger Mode governs the triggering of the measurement on both displays.
Command: TMOD (?) {i}
Trigger Source
Select the Trigger Source [Ch1, Ch2, External, Ext TTL, Source, Manual]. The Trigger
Source does not apply if the Trigger Mode is Free Run.
Ch1 or Ch2 internally trigger on the Ch1 or Ch2 input signal. The trigger is detected after
the anti-aliasing filter (if On).
External and Ext TTL trigger on the front panel Trigger Input. External has a variable
Trigger Level and Ext TTL triggers on TTL signals.
Manual triggers with <Manual Trigger> or an interface command. Use Auto Arm Trigger
Mode with Manual Trigger since unwanted triggers are not a problem.
External, Ext TTL and Manual also trigger the burst Chirp and Noise source waveforms.
Source triggers synchronously with the source waveform. The source runs continuously
and Source Trigger synchronizes the time record with the source waveform. Source
Trigger is not valid for swept sine measurements.
For FFT measurements, the phase of signals which are synchronous with the trigger is
stable. Vector averaging preserves these signals while attenuating random signals, thus
increasing the dynamic range of the measurement.
The Trigger Source applies to both displays.
Command: TSRC (?) {i}
Trigger Level
Set the Trigger Level [-100% .. 99%]. The Trigger Level applies to Ch1, Ch2 and
External Trigger Sources. The Trigger Level is specified as a percentage of the Input
Range for Ch1 or Ch2 and as a percentage of 5 V for External trigger.
The trigger detector requires a minimum signal amplitude of 4% of the Input Range (200
mV for External). For Ch1 or Ch2 internal trigger, the signal must exceed -28 dBfs in
order to trigger. Internal trigger is detected after the anti-aliasing filter (if On).
Command: TLVL (?) {i}