If: No signal Then: number = "0"

Is it possible for no signal to be equal to the number zero. As can be seen in the graph, with no signal I get a constant value from the previous time step, until it receives a signal again. These constantes run horizontally in the graph. Is it possible to equate these horizontal lines to zero?

[KALYAN ACHARJYA]

share your code, then only we can help, what exactly the problem is?

[Ameer Hamza]

How can you decide which output is correct and what is no signal. You mentioned that

"with no signal I get a constant value"

so does this means if you get two constant values like (..., 1, 1, ...) consecutively, the second value is corresponding to no signal. If not? then after how much consecutive constant values, you will be sure that this is no signal.

[Image Analyst]

Do you need to do this on a "live" signal constantly coming in? Or do you want to do this on a signal that has already been captured and put into a variable (possibly after being read in from a file)?

Answer 1

[Jan]

With FEX:RunLength:

[B, N]   = RunLength(Signal);
B(N > 2) = 0;
Signal   = RunLength(B, N);

Now all elements which occur 3 or more times are set to 0.

[Iljar Dickhof]

Thank you for the response.

It sounds logical to use this code, but matlab says to me that he does not know the RunLength command. I do not know if my license is not authorized or if I typed something incorrectly in the code. My code looks like this:

[time, y] = RunLength (simout4);

Then it is giving me the next command:

Undefined function or variable 'RunLength'

[Ameer Hamza]

@Jan mentioned a File Exchange link in the answer. Get it from here: https://www.mathworks.com/matlabcentral/fileexchange/41813-runlength. Download it, place the files on your MATLAB path and then run the command

[Jan]

@Iljar Dickhof: After downloading, you have to compile the C-Mex function (see instructions in the files). If you do not have a C-compiler, you can use RunLength_M from the same submission also. It does the same operation as the C-Mex function, but slower.

[Iljar Dickhof]

Hello,

I installed the C compiler and downloaded the code. All errors are now gone (which I am quite happy with). The graph can be seen in the attached appendix. Thank you for this result.

My code now looks like this:

*>> time = simout4.Time;

>> y = simout4.Data;

>> [B, N] = RunLength (y);

>> B (N> 2) = 0;

>> y = RunLength (B, N);

>> plot (time, y, 'r')

Simout4 is the signal coming from my simulink model.

Now my next question is as follows:

I work in Simulink and wondered if this signal could then be loaded into Simulink again. Then I can use it again in my model.

[Jan]

I do not work with Simulink, so I cannot give a reliable answer. But this is a new question. Please open a new thread, because it allows for keeping the overview, if you post one question per thread only.