What is the method to get step response of differential order system?

Should I do laplace first and then do a step response of the laplace.

I have never used Matlab to such degree and am very confused. There are a lot of links online but none are clear. How do I exactly use the laplace transform in Matlab, how to plug in differential coefficients and order?

laplace(f,trans_var,eval_point)

Then do I use: step(sys,t)

I am so confused why all the examples are not differential equations. I know all about the matlab functions but can never figure out how to input the information. Is there a place where people have very clear SIMPLE examples that will help with signals and systems first course?

Answer 1

[Azzi Abdelmalek]

N=[1 2];
D=[1 7 12]
model=tf(N,D)
[y,t]=step(model)
plot(t,y)

% or

t = 0:0.1:10; % vector time 
u = ones(1,length(t)); u(1:10)=0  
% u is your step signal or a signal of your choice
y=lsim(model,u,t)  
plot(t,y)

[ha9981]

For a person who has never used these function before it is unclear what N and D are. If you can show me the original equation that you found step for then I can learn from it and apply the same technique to my system. Thanks.

[Azzi Abdelmalek]

1 dy^2(t)/dt + 7 dy(t)/dt+12y(t) = dx(t)/dt + 2x(t)

(1 p^2 + 7 p +12) Y(p)=(1 p +2) X(p)

N: contains left polynome coefficients

D: contains right polynome coefficients