[pstricks] si-function
Herbert Voss
LaTeX at zedat.fu-berlin.de
Wed Dec 14 22:26:32 CET 2005
Christoph Bersch wrote:
> Karsten Schmeling schrieb:
>
>>Now I'm writing my Bachelor-work in Latex and I need a si-function to
>>discribe the Method of OFDM.
>>Can someone help me?
>
>
> Hi!
>
> Use the SINC function included in the package pst-math
> <http://www.ctan.org/tex-archive/graphics/pstricks/contrib/pst-math/):
this is only sin(x)/x, but SI(x) is the integral
Herbert
\documentclass{article}
\usepackage{pst-plot}
\usepackage{pst-math,pst-func}
\makeatletter
\def\psSI{\pst at object{psSI}}
\def\psSI at i#1#2{%
\begin at SpecialObj%
\addto at pscode{
/a #1 def
/dx #2 #1 sub \psk at plotpoints\space div def
/b a dx add def
/scx { \pst at number\psxunit mul } def
/scy { \pst at number\psyunit mul } def
tx at FuncDict begin /SFunc { SINC } def end
a scx 0 moveto
\psk at plotpoints 1 sub {
a b \psk at Simpson % a b M on Styack
tx at FuncDict begin Simpson I end % y value on stack
scy b scx exch lineto
/b b dx add def
} repeat
stroke
}%
\end at SpecialObj%
}
\makeatother
\begin{document}
\psset{xunit=0.5cm,yunit=1cm}
\begin{pspicture}(-10,-0.3)(10,1.5)
\psaxes{->}(0,0)(-10,-0.3)(10,1.5)
\psplot[plotpoints=200]{-10}{10}{x SINC}
\end{pspicture}
\vspace{1cm}
\psset{yunit=1cm}
\begin{pspicture}(-10,-.5)(10,4)
\psaxes[dx=1cm,Dx=2]{->}(0,0)(-10,0)(10,4)
\psSI[plotpoints=200]{-10}{10}
\end{pspicture}
\end{document}
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