Pulse Width/Delay (NL405)
A digitally controlled pulse duration generator and is used to produce precise pulses of adjustable duration with high accuracy and repeatability.
The NL405 Pulse Width/Delay is a digitally controlled pulse duration generator and is used to produce precise pulses of adjustable duration with high accuracy and repeatability. This module combines many of the features of the discontinued NL401 Digital Width and NL403 Delay/Width into a single unit.
The NL405 produces TTL logic output pulses (of both polarities) that have a duration set using three decades of thumbwheels and a seven (7) position range switch. It also features a press to start button, LED indication of an output and a separate logic output signal at the end of the defined WIDTH time. It was designed as a replacement for the NL401 and, in most places where the NL403 would have been used.
The NL405 can be triggered off either positive or negative-going edges of the input pulses and the NL405 is capable of 100% duty cycles. An external push to make switch can be used when -ve edge triggering is selected. In the fixed width mode, the NL405 produces an Output pulse as specified by the front panel controls. In the RE-TRIGGER mode, any valid Input trigger arriving whilst the Output is active will restart the timing and therefore extending the Output pulse duration.
As long time periods can be generated (999 seconds is over 16 minutes) any change in position of the rotary range switch will stop the current Output and inhibit further input triggers for 500ms. The delayed Output socket provides a short duration pulse (set internally) that is produced at the end of the timed width pulse. This provides a trigger-out after the set Delay time. The NL405 can be used for digital control of pulse duration or for introduction of a delay to a trigger pulse. The logarithmic or exponential nature of the many biological responses make the very wide continuous adjustment (from micro seconds to minutes) particularly beneficial.
|Input||TTL pulse. Input is 1 TTL load.|
|Trigger edge||Positive or Negative, selected from front panel|
|Manual||Push-button, operation on push.|
|Output (Width)||TTL. Output will drive 10 loads.|
|Polarity||Both active-high and active-low sockets|
|Range||1 µs to 999 s|
|Control||001 to 999|
|Multiplier||1 µs, 10 µs, 100 µs, 1 ms, 10 ms, 100 ms, 1 s|
|Delay from Trigger In||<200 ns|
|Indicator||Amber LED on for approximately 10 ms for each pulse|
|Output (Delay)||TTL. Output will drive 10 loads|
|Duration||0.5 µs, 1.5 µs, 5 µs ± 20%|
|50 µs, 150 µs, 500 µs ± 10%, by on-board jumpers|
|Mode||Fixed Width or Re-Triggered, selected from front panel|
|Reset/Inhibit||450 ms ± 20%, after change of rotary range control|