unit_functions

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unit_functions

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{ UNIT_FUNCTIONS.PDE  

 

This example illustrates the unit step, unit pulse,

and unit ramp functions ustep(arg1), upulse(arg1,arg2),

and uramp(arg1,arg2) See Unit Functions.

 

}  

 

title  

"unit functions"  

 

select  

 elevationgrid=500  

 

{no variables}  

 

definitions  

 x1 = 0.2  

 x2 = 0.4  

 

{no equations}  

 

{plot domain -- required}  

boundaries  

region 1  

  start (-1,0)  

  line to (1,0) to (1,1) to (-1,1) to close  

 

plots  

elevation(ustep(x-x1)) from (0,0) to (1,0)  

elevation(dx(ustep(x-x1))) from (0,0) to (1,0)  

elevation(upulse(x-x1,x-x2)) from (0,0) to (1,0)  

elevation(dx(upulse(x-x1,x-x2))) from (0,0) to (1,0)  

elevation(uramp(x-x1,x-x2)) from (0,0) to (1,0)  

elevation(dx(uramp(x-x1,x-x2))) from (0,0) to (1,0)  

! generating a square wave by clipping a cosine  

elevation(ustep(cos(4*pi*x))) from (-1,0) to (1,0)  

! the duty cycle can be controlled by offsetting the cosine from zero

elevation(ustep(cos(4*pi*x)-0.3)) from (-1,0) to (1,0)  

 

end