Problem with Frequency distribution plot

I have a scatter plot in (x, z). I need to plot a frequency distribution of z-values as a function of x. Please suggest.

[Torsten]

A frequency distribution of z-values is a plot where the x-axis are the z-values and the y-axis shows the frequency of the z-values.

But what is a frequency distribution of z-values as a function of x ?

[Torsten]

So the z-value doesn't matter ? Then simply use histogram(x).

[Image Analyst]

This is a poorly worded question. Perhaps frequency distribution means histogram. I was thinking it was like a signal and he wanted the frequency spectrum of the signal. But it looks like @AkB is ignoring our comments, so I'm not going to do anything more until we hear back from @AkB with a clearer explanation of what the context/situation is.

[Torsten]

@Image Analyst

I think he/she is unsure about it himself/herself.

Answer 1

[Image Analyst]

If x is not uniformly spaced then use interp1 or spline to get x and z uniformly spaced. Then call fft(z).

ft = fft(z);
plot(abs(ft), 'b-');