Math Forum Discussions

aniket

Posts: 23
Registered: 1/15/13

trying to plot difference between input frequency and estimated frequency ?
Posted: Feb 6, 2013 6:00 AM

Plain Text

hello ,

I want to plot a graph of difference between input signal frequency and adapted frequency . how should i do it ?

here is my code

in this,

fin is input signal frequency

y(3) mention in function is oscillator initial frequency

dz(3) mention in function is learning rule for oscillator frequency, because of this oscillator adapts input signal frequency.

i want to plot difference of fin and dz(3)

for example
D = fin - dz(3)

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function dz = myeqd(t,y,ti,fi)

dz = zeros(3,1);

mu=0.7;

r= sqrt(y(1)^2 + y(2)^2);

K=2;

F=interp1(ti,fi,t);

dz(1)= (mu - r^2)*y(1) - y(3)*y(2) +K*F;

dz(2) = (mu - r^2)*y(2) + y(3)*y(1);

dz(3) = (-K*F) * (y(2)/sqrt(y(1)^2 + y(2)^2));

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then call this function

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Tspan= 0:0.01:500; % time vector

fin = 10;

fi = cos(fin*Tspan); % external perturbation

ti=Tspan;

[T,Y]=ode45(@(t,y) myeqd(t,y,ti,fi),Tspan,[1;1;30]);

plot (T,Y(:,3))

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