Stanford Research Systems SR785, Operating Manual And Programming Reference

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4-102 Trigger Menu
SR785 Dynamic Signal Analyzer
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}
Trigger Slope
Select the Trigger Slope [Rising, Falling]. The Trigger Slope applies to Ch1, Ch2,
External and Ext TTL Trigger Sources.
Command: TSLP (?) {i}
Delay 1
Set the Trigger Delay for Ch1, or Display A. depending on the Analyzer Configuration.
The Trigger Delay applies only to FFT and Correlation measurements.
When the Analyzer Configuration is Dual Channel, the delay setting affects the Ch1
input. When the Analyzer Configuration is Independent Channels, the delay setting
affects the measurement displayed in Display A.
The triggered time record does not have to start with the trigger event. The time record
can start before the trigger (negative delay) or after the trigger (positive delay). A delay
of 0 starts the time record at the trigger. The Trigger Delay does not apply if the Trigger
Source is Continuous.
The trigger delay can range from -8,000 to +100,000 times the underlying FFT sample
rate.
When a large trigger delay is used, the display may update more slowly since the
acquisition time for each record (time record length plus trigger delay) is noticeably
long.
Command: TDLA (?) {i}
Delay B
Set the Trigger Delay for Ch1, or Display A. depending on the Analyzer Configuration.
The Trigger Delay applies only to FFT and Correlation measurements.