Multichannel Systems STG1000 Manual - Manual (Page 49)

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10 Synchronizing Events
10.1 Digital Output Signals (Sync Out)
The output of the digital Sync Out output is a 5 V TTL signal. A logic state of 1 means 5 V, and a
logic state of 0 means 0 V. Please note that the digital output is about 15 μs faster than the
analog output. This small offset is generally sufficient to make sure that the Sync Out signal
precedes the stimulation, which is important for synchronizing events.
You can program the output signal of the Sync Out channel in the same way as the analog output
signals, but due to the nature of a digital signal, only values of 0 and 1 are allowed. A Sync Out
signal is generated each time when the STG is started.
The output signal can be used for triggering external devices, for example, the data
acquisition with the MC_Card of the ME System and the MEA System. Please note that if you
use it for triggering the MC_Card, you should use output signals that have a duration of at least
200 μs. Otherwise, it can happen that the MC_Card ignores trigger events.
Note: No Sync Out signal is sent when the STG is stopped on a trigger event or by pressing the
Start/Stop button, that is, if the trigger event occurs or the button is pressed when the STG has
still been active.
Timing of blanking signal
If you have a MEA amplifier with blanking circuit in use, you can apply a blanking signal (TTL
pulse) for transiently switching off the input stage of the amplifiers during the stimulus, thus
avoiding the stimulus artifact.
MCS recommends a minimum blanking pulse that starts with the stimulus and stops 100 μs after
the stimulus. The fact that the digital output of the stimulus generator from MCS is about 15 μs
faster than the analog output ensures that the blanking signal is delivered before the stimulus. It
is very important that the blanking pulse is delivered shortly before the stimulus.
The following example shows a blanking signal (programmed with MC_Stimulus) of 300 μs length
for a biphasic pulse of 200 μs length. See also the MEA_Select Help or the MEA Amplifier with
Blanking Circuit User Manual for more information.
You can use the Auto Sync feature for autocreating the Sync Out pulses without entering values
manually. Please see "Auto Sync for Autocreating Synchronous Sync Out Pulses".