MATLAB: I need to filter this ode45 sine wave becomes a smooth one…

filterFilter Design Toolboxfilter ode45 sine wavelowpass filterode45sine wave filter

i used this line of code, and i implement Lowpass FIR filter, but maybe the code i used is wrong somewhere. can anybody help me fixed this
error popped is 'Index exceeds Matrix dimension' and 'Error using forced (line 2),Not enough input arguments.'
these are the codes
EDITOR: function dxdt = forced(t,x) dxdt_1 = x(2); dxdt_2 = -100*x(2)-250000*x(1)+ ((25000)*((0.00002)*sin(2.6735*t))^3); dxdt = [dxdt_1;dxdt_2];
COMMAND WINDOW: tspan=[0:0.1:20]; initial_x=0; initial_dxdt=0; [t,x]=ode45(@forced,tspan,[initial_x initial_dxdt]); figure plot(t,x(:,1)); grid on %UNTIL HERE IT WORKS FINE
fHandle=@forced; Fs=20; fc=3; t=linspace(0,0.1,Fs); Wn=(2/Fs)*fc; b=fir1(20,Wn,'low',kaiser(21,3)); fvtool(b,1,'Fs',Fs)
z=filter(b,1,fHandle());
plot(t(1:100),fHandle()(1:100)) hold on plot(t(1:100,z(1:100)) xlabel('Time(s)') ylabel('Amplitude') legend('Original Signal','Filtered Data') %the error appear here…
any suggestion or helps, much thanks.

Best Answer

Hi Akil
I think you need this, of Course I am not sure about the technical point of view
Function:
function dxdt = forced(t,x)
dxdt_1 = x(2);
dxdt_2 = -100*x(2)-250000*x(1)+ ((25000)*((0.00002)*sin(2.6735*t)).^3);
dxdt = [dxdt_1; dxdt_2];
Command Windows
clear
clc
tspan=[0:0.1:20];
initial_x=0; initial_dxdt=0;
[t,x]=ode45(@forced,tspan,[initial_x initial_dxdt]);
figure 
plot(t,x(:,1));
grid on
fHandle=forced(t,x); 
Fs=20; 
fc=3; 
t=0:0.1:Fs; 
Wn=(2/Fs)*fc;
b=fir1(20,Wn,'low',kaiser(21,3));
fvtool(b,1,'Fs',Fs)
z=filter(b,1,fHandle);
plot(t(1:100),fHandle(1:100))
hold on 
plot(t(1:100),z(1:100)) 
xlabel('Time(s)') 
ylabel('Amplitude') 
legend('Original Signal','Filtered Data')
Regards,
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