Non-linear axis plotting
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Background: Many years ago when plotting reciever error rate against input power I used graphpaper that was designed to give a straight line if the performance followed theory. That made it easy to spot problems (like hitting a noise floor) as plot would diverge from a straight line. Some years later it became harder to find this special paper, so I wrote a simple plotter in Java to do this.
Question: How do I do this in MATLAB? The y-axis is non-linear would ned to use the inverse complimentary error function (so y in linear space = log10(erfcInv(BER)). This question is not about how to write erfcinv(), but how about how to get the plot's y-axis to do this.
Example: - On the left: My old Java plot application, on the right a MATLAB plot using semilogy(power, BER) using the same data for reference. Not that my old BER plot grids very in size.
![Example plots](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1571147/Example%20plots.png)
Here my MATLAB code that made the sample plot on the right on the picture:
function sample()
data = [
-38, 1e-3;
-37, 3.8e-4;
-36 1.2e-4;
-35 3.4e-5;
-34 7e-6;
-33 1.35e-6;
-32 1.8e-7;
-31 1.8e-8;
-30 1e-9;
];
power = data(:,1);
BER = data(:,2);
semilogy(power,BER)
grid on
end
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Answers (1)
Star Strider
on 17 Dec 2023
2 Comments
Star Strider
on 19 Dec 2023
My pleasure!
The axis labels are properties that can be changed, and this varies with the type of plot.
Using an example from the probplot documentation, this works —
y = 1:10;
freq = [2 4 6 7 9 8 7 7 6 5];
figure
probplot(y,[],freq)
Ax = gca;
Ax.YLabel.String = "BER";
The axis labels are axes properties. The gca call returns a handle to them, and then since the ‘YLabel’ propertiy has several specific properties of its own, setting its ‘String’ property changes the label text.
Consider requesting the sort of plot you want as an addition to the Communications Toolbox (since that appears to be what you have and are using). To do that, Contact Support and ask. Include the URL to this thread so they can refer to it.
.
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