Avtech AV-1010-C-MI Instructions Manual page 17

Fig. 6
THRESHOLD MODULE
The threshold module acts as a buffer for the EX? TRIG
input. The module accepts trigger inputs of +@.5V to
+40V in amplitude and generates a 300 ns T output
pulse when the input passes a certain threshold voltage,
set by the LEVEL knob on the front panel./ When' the
threshold voltage is negative, the module will trigger
when the input is more negative than the threshold.
When the threshold voltage is positive, the module will
trigger when the input is more positive than the
threshold.
Pin connections
1. No connection
2. Input, connected to "EXT TRIG" BNC connector on
the front panel
3. -15V input
4. TTL Out (to pin 15 of clock module)
5. Ground
6. Ground
7. +5V input
8. +15V input
9. Level. This pin is connected to the front panel
"LEVEL" potentiometer. The voltage on this pin
is proportional to the trigger threshold. The
voltage ranges between -15V and +15V, which sets
the threshold at +40V and -40V, respectively.
10. No connection