Scicos Block
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Non-linear tunning caracteristic of Voltage Controled Oscillator block

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Contents

Palette

Description

This block realizes an hyperbolic tangent function. The output is computed by the formula :

$\displaystyle y=F\left(u\right)=\alpha \tanh\left(\beta u\right)
$

where $ \alpha$ is a gain parameter exprimed in [rad/s] and $ \beta$ a coefficient parameter (no unit). $ \tanh()$ is the hyperbolic tangent function defined by :

$\displaystyle \tanh\left(x\right)=\frac{\exp(x)-\exp(-x)}{\exp(x)+\exp(-x)}
$

Y outputs represents a pulsation deviation in accord to u inputs that represents an input voltage. The Fig.[*] shows a static deviation given to $ \alpha$=6.91e+9 rad/s and $ \beta$=0.15.
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Figure : Static Voltage/Pulsation characteristic for $ \alpha$=6.91e+9 rad/s and $ \beta$=0.15.

Super block equivalent model

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Dialog box

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Default properties

Interfacing function

VTUNE_f.sci

Computational function (type 2)


/* tanhblk Scicos hyperbolic tangent block
 * Type 2 simulation function ver 1.0 - scilab-2.6&2.7
 * 13 octobre 2003 - IRCOM GROUP - Author : A.Layec
 */

/* REVISION HISTORY :
 * $Log$
 */
  
#include "machine.h"
#include<math.h>

/* Ce bloc réalise l'opération y[0]=rpar[0]*tanh(rpar[1]*u[0])
 * entrées régulières : vecteur des entrées u[0..nu-1]
 * sorties régulières : vecteurs des sorties y[0..nu-1]
 * entrées et sorties d'évenement : néant
 * paramètres rélls rpar[0..nu-1] : vecteur du gain
 *                  rpar[nu..2*nu-1] : vecteur du coefficient
 */
 
/*prototype*/
void tanhblk(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,rpar,nrpar,
             ipar,nipar,inptr,insz,nin,outptr,outsz,nout)
integer *flag,*nevprt,*nx,*nz,*ntvec,*nrpar,ipar[],*nipar,insz[],*nin,outsz[],*nout;
double x[],xd[],z[],tvec[],rpar[];
double *inptr[],*outptr[],*t;
{
 /*déclaration des variables*/
 double *y;
 double *u;
 double t1,t2;
 int i,nu;

 /*récupération des adresses des ports réguliers*/
 y = (double *)outptr[0];
 u = (double *)inptr[0];
    
 /*récupération de la taille du port d'entrée*/
 nu=insz[0];

 for(i=0;i<nu;i++)
 {
  t1=exp(rpar[nu+i]*u[i]);
  t2=exp(-rpar[nu+i]*u[i]);
  y[i]=rpar[i]*((t1-t2)/(t1+t2));
 }
}

See also

Authors

IRCOM Group Alan Layec