3 analog trigger, Analog trigger – ADLINK PCI-9846 User Manual
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Operation Theory
3.4.3 Analog Trigger
You can choose either CH0, CH1, CH2 or CH3 as the trigger sig-
nal while using external analog trigger source. The trigger level
can be set by software with 8-bit resolution. Please refer to
Table 3-3 for the ideal transfer characteristic.
The trigger conditions for analog triggers are illustrated in
Figure 3-9 and described as follows:
Positive-slope trigger: The trigger event occurs when the
trigger signal (analog input signal) changes from a voltage
that is lower than the specified trigger level to a voltage that
is higher than the specified trigger level.
Negative-slope trigger: The trigger event occurs when the
trigger signal (analog input signal) changes from a voltage
that is higher than the specified trigger level to a voltage that
is lower than the specified trigger level.
Trigger Level
Setting (Hex)
Trigger Voltage
(-1V to +1V Range)
Trigger Voltage
(-0.2V to +0.2V)
0xFF
0.992V
0.1984V
0xFE
0.984V
0.1968V
---
---
---
0x81
0.0078V
1.56mV
0x80
0V
0V
0x7F
-0.0078V
-1.56mV
---
---
---
0x01
-0.992V
-0.1984V
Table 3-3: Ideal Transfer Characteristics for Analog Triggers