Mode Gated Sampling
Trigger
(c) Spectrum GmbH
117
Channel pulsewidth trigger for long positive pulses
The analog input is continuously sampled with the selected
sample rate. If the programmed trigger level is crossed by
the channel’s signal from lower to higher values (rising
edge) the pulsewidth counter is started. If the signal crosses
the trigger level again in the opposite direction within the
the programmed pulsewidth time, no trigger will be detect-
ed. If the pulsewidth counter reaches the programmed
amount of samples, without the signal crossing the trigger
level in the opposite direction, the gate will start.
If the programmed trigger level is crossed by the channel’s
signal from higher to lower values (falling edge) the gate
will stop.
The pulsewidth trigger modes for long pulses can be used to prevent the board from triggering on wrong (short) edges in noisy signals.
Channel pulsewidth trigger for long negative pulses
The analog input is continuously sampled with the selected
sample rate. If the programmed trigger level is crossed by
the channel’s signal from higher to lower values (falling
edge) the pulsewidth counter is started. If the signal crosses
the trigger level again in the opposite direction within the
the programmed pulsewidth time, no trigger will be detect-
ed. If the pulsewidth counter reaches the programmed
amount of samples, without the signal crossing the trigger
level in the opposite direction, the gate will start.
If the programmed trigger level is crossed by the channel’s
signal from lower to higher values (rising edge) the gate will
stop.
The pulsewidth trigger modes for long pulses can be used to prevent the board from triggering on wrong (short) edges in noisy signals.
Channel window trigger for entering signals
The analog input is continuously sampled with the selected
sample rate. The upper and the lower level define a win-
dow.
When the signal enters the window from the outside to the
inside, the gate will start.
When the signal leaves the window from the inside to the
outside, the gate will stop.
As this mode is purely edge-triggered, the signal outside the
window at the cards start time does not trigger the board.
Register
Value
Direction
set to
Value
SPC_TRIG_CH0_MODE
40610
read/write
SPC_TM_POS | SPC_TM_PW_GREATER
04000001h
SPC_TRIG_CH0_LEVEL0
42200
read/write
Set it to the desired trigger level relatively to the channel’s input range.
board dependant
SPC_TRIG_CH0_PULSEWIDTH
44101
read/write
Sets the pulsewidth in samples. Values from 2 to 65535 are allowed.
2 to 65535
Register
Value
Direction
set to
Value
SPC_TRIG_CH0_MODE
40610
read/write
SPC_TM_NEG | SPC_TM_PW_GREATER
04000002h
SPC_TRIG_CH0_LEVEL0
42200
read/write
Set it to the desired trigger level relatively to the channel’s input range.
board dependant
SPC_TRIG_CH0_PULSEWIDTH
44101
read/write
Sets the pulsewidth in samples. Values from 2 to 65535 are allowed.
2 to 65535
Register
Value
Direction
set to
Value
SPC_TRIG_CH0_MODE
40610
read/write
SPC_TM_WINENTER
00000020h
SPC_TRIG_CH0_LEVEL0
42200
read/write
Set it to the upper trigger level relatively to the channel’s input range.
board dependant
SPC_TRIG_CH0_LEVEL1
42300
read/write
Set it to the lower trigger level relatively to the channel’s input range.
board dependant
