VTUNE_f

Scicos Block
fr - eng

Nonlinear tunning characteristic of Voltage Controlled Oscillator block

$\epsfig{file=VTUNE_f.eps,height=90pt}$

This block computes an hyperbolic tangent function. The output of this block is given by the following expression :

$\begin{eqnarray} y=F\left(u\right)=\alpha \tanh\left(\beta u\right) \end{eqnarray}$

with

Remember that tanh() is the hyperbolic tangent function defined by :

$\begin{eqnarray} \tanh\left(x\right)=\frac{\exp(x)-\exp(-x)}{\exp(x)+\exp(-x)} \end{eqnarray}$

In fact the output of this block provides a frequency deviation depending of the input voltage. The Fig.1 shows an example of this static function.

$\begin{figure}\centering \scalebox{0.5}{% \input{vtune_fig.pstex_t}} \end{figure}$

Figure 1: Static Voltage/Pulsation characteristic (alpha=6.91e9 rad/s, beta=0.15).

$\epsfig{file=VTUNE_f_sbeq.eps,height=1.5cm}$

$\begin{figure}\begin{center} \epsfig{file=VTUNE_f_gui.eps,width=300pt} \end{center}\end{figure}$

Gain
The alpha gain of the nonlinear characteristic.
Properties : Type 'vec' of size -1.
Coefficient
The beta coefficient of the nonlinear characteristic.
Properties : Type 'vec' of size -1.
Plot function (0:no or winid)
Draw the nonlinear characteristic in a scilab window if the value of this dialog parameter is greater than zero.
Properties : Type 'vec' of size 1.

A. Layec

[1] S. Sancho, A. Suarez, and T. Fernandez, ``Nonlinear dynamics of microwave synthesizers. stability and noise,'' IEEE Trans. Microwave Theory Tech., vol. 49, no. 10, pp. 1792-1803, Oct. 2001.