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# "repeating sequence" block dysfunction

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## "repeating sequence" block dysfunction

(OP)
MATLAB Version 7.3 (R2006b)
Simulink Version 6.5 (R2006b)

Hello,

Could somebody tell me what is the reason of the problem that I encounter about the shape of the signal produced by a Repeating Sequence block ?

I try to generate a square signal with the Repeating Sequence block but it yields a saw-shaped signal. Besides it doesn't follow the right schedule. However, the same block, with the same parameters provide the right signal in another model. When I copy it and paste it in my model, it doesn't work anymore.
I really don't know where this problem comes from. Does somebody has an idea ? Thank you.
Replies continue below

### RE: "repeating sequence" block dysfunction

With the repeating sequence block you enter two vectors one for y-positions and one for time. So,
[0,1,1,0]
[0,1,2,3]
creates a trapazoid pulse signal where as
[0,0,1,1,0,0]
[0,1,1.001,2,2.001,3]
creates more of a square pulse signal

Using the repeating sequence to do a square waves is not necesarry as there should be a signal generator block that allows one to select wave form, amplitude, and frequency. The wave forms being sine, square, sawtooth, random.

However if you still wish to use the repeating sequence block I hope the initial explaination solves your problem.
Regards,
BsK

### RE: "repeating sequence" block dysfunction

(OP)
I know how to create a sequence.
The problem was that I used an automatic step size wich don't creates enough samples to build the square signal. I set a proper "max step size" to solve the problem.
The reason why it works well in the other model is that it is more complex and more dynamic, so that the automatic variable step size creates more samples.

Thanks anyway ;)

### RE: "repeating sequence" block dysfunction

Did you try the signal generator block? It might force a system step size necessary to allowfora true square wave.

### RE: "repeating sequence" block dysfunction

(OP)
I had tried the signal generator block but it seems that it doesn't allow to built a signal with different time steps (squares of different sizes in the same sequence). Anyway I couldn'nt find how to do that whereas this is what I needed.

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