Graphing 3D Z-Transform in MATLAB

[enceladus_]

Does anyone know how I might go about graphing the Z-Transform in 3D? It want it to look something like the picture below.

 

[kreil]

Are you interested in knowing how to plot in 3D, or how to calculate the z transform? Do you have access to Symbolic Math Toolbox? If so, there are some helpful functions in it for doing z transforms. I don't think core MATLAB has a function for it but there is probably something on the file exchange. This may also be relevant:

http://www.mathworks.com/help/matlab/data_analysis/filtering-data.html#bqm3i7m-5

Otherwise, the plot you're looking at probably came from using meshgrid() and surf(), then overlaying the unit circle values with a call to plot3().

 

[enceladus_]

More so plotting in 3d, I've never used meshgrid or surf before. I do have access to the Symbolic Toolbox. Would I have to use BOTH meshgrid() and surf()?

 

[enceladus_]

I have found this code from another site:

xmin = -2; xstep = 0.1; xmax = 2;
ymin = -2; ystep = 0.1; ymax = 2;
x = xmin : xstep : xmax;
y = ymin : ystep : ymax;
[X,Y] = meshgrid(x,y);

Z = 10*log10(abs(test(X + j*Y))); % here is the call to the function to be plotted.
Z2 = abs(X + j*Y) <=1; % Here is the mask the zeros things outside the unit circle

hold off
surf(X, Y, Z) % Draw and label the surface
colormap(cool)
xlabel('Re')
ylabel('Im')

ww=-pi:pi/25:pi;

[xn, yn, zn] = freqMove(0, ww);
hold on
plot3(xn, yn, zn)

It generates the following error:

Undefined function 'test' for input arguments of type 'double'.

Error in hmm (line 7)
Z = 10*log10(abs(test(X + j*Y))); % here is the call to the function to be plotted.

 

[alphy]

I am familiar with the Z-Transform and its applications in signal processing and control systems. To graph the Z-Transform in 3D using MATLAB, you can use the "mesh" function. This function creates a mesh plot, where the Z-Transform values can be plotted in a three-dimensional space. You can specify the values of the independent variables (usually frequency and time) and the Z-Transform function itself, and the plot will show the values of the Z-Transform at different points in the 3D space.

To make the plot look similar to the picture provided, you can adjust the color and style of the plot using the "colormap" and "surf" functions in MATLAB. Additionally, you can use the "view" function to change the perspective of the plot and make it look like it is rotating in space.

It is important to note that the Z-Transform is a complex function, so the plot will have a real and imaginary component. Therefore, the 3D graph will have two surfaces, one for the real part and one for the imaginary part, which can be distinguished by using different colors or shading.

In conclusion, by using the appropriate functions in MATLAB, you can easily create a 3D graph of the Z-Transform that resembles the picture provided. It is a useful tool for visualizing the Z-Transform and gaining a better understanding of its behavior in three-dimensional space.