How to split signal in simulink?

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George Francis
George Francis on 20 Mar 2018
Edited: Jim Riggs on 21 Mar 2018
Hello, I have this easy model. In matlab function block I have command ulength=length(u); and it returns me 1. It should give me 30, because in red box is set time to 30. My question is if I can split somehow the signal, because I need to use in matlab function block for loop: For example:
for k=1:30
z= [-y(k-1) u(k-1)]';
end
But it shows me error: that signal 'u' and 'y' are one dimensional with one element. So is there way how to split that signal so I could work with it like in matlab workspace?
  2 Comments
Birdman
Birdman on 20 Mar 2018
What are you going to do by splitting them? Explain that and maybe we'll come up with an easier way.
George Francis
George Francis on 20 Mar 2018
I have to identify data using recursive least square method which should give me 4 parameters (b0,a2,a1,a0).
b0
--------------
a2*s^2+a1*s+a0
My code which I have in matlab works fine but in simulink it doesn't work because of the loop. It won't let me access y(n-l) how it shown below because it says it's one dimensional with 1 element so dunno how to change the code that it would work in simulink.
for n=3:N
for l=1:1
V(l) = y(n-l); %output
end
for i=1:3
W(i) = u(n-i+1); %input
end
z = [V';W'];
sample_out = y(n);
C = (C - ( (C*z*z'*C)/( lamda+(z'*C*z) ) ))/lamda;
P = P + (C*z* (sample_out - (z'*P) ) );
end

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Accepted Answer

Jim Riggs
Jim Riggs on 20 Mar 2018
Edited: Jim Riggs on 20 Mar 2018
I'm not sure if this is the answer to your question, but Here is how to access a signal from the previous calculation iteration, y(n-1), in Simulink:
  2 Comments
George Francis
George Francis on 21 Mar 2018
Thank you for help, I actually found that I can use also unit delay block instead of memory block.
Jim Riggs
Jim Riggs on 21 Mar 2018
Edited: Jim Riggs on 21 Mar 2018
Very good.
The memory block may be set to any delay you desire.
n-1, n-2, n-3, .... etc.
you specify the delay inside the block. Default is 1.

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