Object Type:	pulsegen

Description:	General purpose pulse generator

Author:		M. Nelson, Caltech (4/89)

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ELEMENT PARAMETERS

DataStructure:	pulsegen_type  [in src/user/user_struct.h]

Size:		120 bytes

Fields:		level1		level of pulse1
		width1		width of pulse1
		delay1		delay of pulse1
				  (wrt ext. input - trig or gate mode)
				  (wrt pulse2     - free run mode)
                level2		level of pulse2
		width2		width of pulse2
		delay2		delay of pulse2 (wrt pulse1)
		baselevel	baseline level
		trig_mode	flag: 0=free run, 1=ext. trig, 2=ext. gate
		output		output
		trig_time	internal state variable
		previous_input	internal state variable

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SIMULATION PARAMETERS

Function:	PulseGen  [in src/user/pulsegen.c]

Classes:	device

Actions:	PROCESS  RESET

Messages:	INPUT "gate/trig"   (0 = low, non-0 = high)
		LEVEL pulse# level
		WIDTH pulse# width
		DELAY pulse# delay

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Notes:

This device can generate a variety of pulse patterns:  single pulses, double
pulses (each with its own level and width), and pulse trains (of single
pulses or pairs).  It can be triggered, gated, or allowed to free run.

In combination with a spikegen object, it can be used to generate bursts of
spikes for use as synaptic input.  (See Scripts/neuron/inputs.g.)

The following diagram illustrates the relationships between the fields:

                      +-----------------+ level1
  trigger             |                 |
     |                |                 |        +-------------+ level2
     |                |                 |        |             |
     V                |                 |        |             |
     +--- baselevel --+                 +--------+             +----

     <---- delay1 ----><---- width1 ---->         <-- width2 -->
                       <--------- delay2 -------->
If delay2 <= width1, then level2 starts imediately after the end of the
pulse at level1.  This means that if delay2, width2 and level2 are not set
and remain at their default values of 0, there will be only one type of
pulse.  It will repeat after a time delay1 after the end of the pulse
(free run mode) or a time delay1 after it is triggered (trigger or gate
mode).


Example:	Scripts/examples/pulsegen/PulseGenDemo.g

See also: