THORLABS SPDMA Operation Manual page 10

SPDMA 3 Operating Instructions
Whenever a TTL trigger input signal is used, the default TTL input needs to be "Low". Signal
from photon detection is sent to Pulse Out as the Trigger Input voltage switches to "High". High
and Low signal are specified in the section Technical Data.
Note
W
"Trigger In" and "Pulse Out" are of a 50 impedance. Make sure that the trigger pulse source
W
is capable to work on a 50 load and that the device connected to "Pulse Out" operates at a
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50 input impedance.
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