Spikes in my heaviside function/step functions

Question

Samantha Zhao 2019-2-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/447160-spikes-in-my-heaviside-function-step-functions

评论： Samantha Zhao 2019-3-7

I am trying to plot a simple unit step function (below) using the heaviside function.

x(t) =u(t)−u(t−2)

t = -10:.01:10;
x = heaviside(t) - heaviside(t-2);
plot(x)

The plot results in a unit step function with spikes at 4 and -3.

So far my solutions have been editing in the correct values at the appropriate indexes, but it has been getting very tedious. What could be causing this issue? I am also using the 2018b edition and have not noticed this in previous versions.

2 个评论
显示无隐藏无

Asad Mirza 2019-2-26

编辑：Asad Mirza 2019-2-26

Not sure why but when I run the code it comes out without any strange spikes. I am also using MATLAB 2018b.

Just checked it with both MATLAB Online and Octave and I get the same results

Walter Roberson 2019-3-1

Also, be careful about what heaviside(0) means. See sympref('HeavisideAtOrigin')

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Munish Raj 2019-3-1

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/447160-spikes-in-my-heaviside-function-step-functions#answer_363273

在 MATLAB Online 中打开

Hello Samantha,

The plot in your picture is a mixture of two different plots. It has the intended heaviside as expected.

As you can notice, the y axis of the plot is from [-3 4]. However, the expected heaviside function is plotted in [1 0] on the y axis.

Also please make sure there is no previous plot.

Use the hold off command before plotting the heaviside function.

hold off

to make sure that a new plot is being plotted.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Munish Raj 2019-3-7

The red highlighted plot is the heaviside plot that you are looking for.

The other parts are the extra plots, possibly from another plot function.

Samantha Zhao 2019-3-7

I have reinstalled Matlab, opened up a new script, and made sure that there is nothing else being plotted with my heaviside. I'm really at a loss expecially when others are able to produce a normal graph with the exact code!

请先登录，再进行评论。