SIMULINK - how to make a VCO

[Steven P. Krekeler]

I am interested to know if anyone has successfully implemented a
Voltage-Controlled Oscillator or a frequency modulator block in
Simulink, or if anyone can suggest a way to do so.

Thanks.

--
Steve
--
- ste...@alumni.caltech.edu

[Dr W Tych]

In article: <2t5rji$m...@gap.cco.caltech.edu>

ste...@alumni.caltech.edu (Steven P. Krekeler) writes:

> I am interested to know if anyone has successfully implemented a
> Voltage-Controlled Oscillator or a frequency modulator block in
> Simulink, or if anyone can suggest a way to do so.

One way of doing this is to remember that :

y''+w^2*y=0

is the oscillator with frequency w. Now you can build it in
Simulink, using a variable w:

__
w >--------| |
|* |------[integr]---[integr]------> output
|-[-1]--|__| |
|______________________________________|

Output will be a sine-wave with frequency w. Remember to
initialise the second integrator to the value related to the
amplitude you want (the exact relationship I leave as an excercise).
If you leave it at zero, it will remain there, as the trivial solution
y=0 also satisfies the equation.

If you want a more serious VCO, you could make an S-function from that.

Have fun,

Wlodek

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