Extech Instruments 400790A, User Manual

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3.7 Trigger Mode Setup and Operation
A measurement can be initiated by one of three triggers: time trigger (time ‐ controlled
triggering), level trigger (sound level controlled triggering), and external trigger (triggering by an
external signal).
Level trigger 1 : Measurement starts when the trigger level is exceeded and ends after the
measurement time.
The trigger level is valid at any time.
Setting items:
Trigger Slope Type: +, ‐
Trigger Level: 25 to 130dB, 1 ‐ dB steps.
Trigger Band: MAIN AP /31.5Hz/63Hz/125Hz….8kHz (1/3 octave bands)
Level trigger 2 : Single measurement is made when trigger level is exceeded.
The trigger level is valid at any time.
Setting items:
Trigger Level: 25 to 130dB, 1 ‐ dB steps.
Trigger Band: MAIN AP /31.5Hz/63Hz/125Hz…8kHz (1/3 octave bands).
Time trigger : This is a reoccurring trigger timer that starts a measurement after a trigger timer.
The measurement ends after the measurement time.
The trigger timer is valid at all times.
Setting items:
Trigger Time: h:m:s
External trigger : A Measurement starts at falling edge of a logic ‐ level (0 to 5V logic) signal at the
external trigger input. A Pulse width of 1ms or more is required.
The external trigger is valid at all times
.
Trigger Operation ‐ example
1. Sound Level
2. Time
3. Slope + Trigger
4. Slope ‐ Trigger
5. Trigger Level
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