Plotting the Complex spectrum of a converted signal

My goal in this program is to plot the complex spectrum of multiple signals after they are converted into complex exponentials.

syms t
a = 10 * pi * t + 20;
b = 12 * pi * t - 40;
c = 15 * pi * t + 60;

A = rewrite(8 + 6*cos(a) - 3*cos(b) + 10 *sin(c) ,'exp')
AE = expand(A)

This gives me a desired output however whenever I try to plot the complex spectrum using

k = linspace(0,10);
r = subs(P, t, k)

Then I run into issues. Is there a more direct approach where I can take A or AE and directly plot the complex spectrum ? Or does AE need to be converted into a matrix and then plotted?

The current error I run into when trying to plot the complex spectrum like I normally do is this

% Error using plot
% Data must be numeric, datetime, duration or an array convertible to double.

Answer 1

[Star Strider]

Whatever ’P’ is, is missing, however that is of no consequence.

Use the fplot function to do the plotting:

figure
fplot(real(AE))
hold on
fplot(imag(AE))
hold off
grid
legend('Re','Im')

.

[David Wisniewski]

Wow that works great. Is there a way to get it in the form that is represennted by line segments?

[Star Strider]

It likely is, however I don’t understand what you mean by ‘line segments’. Nothing in your original post alluded to that.

[David Wisniewski]

Thank you I am just starting out in DSP when I say line segments I mean in this form I am still working on the vocabulary.

[Star Strider]

That is a stem plot. There is no ‘fstem’ function, so it takes a bit of handle magic to get the data and then plot it:

syms t
a = 10 * pi * t + 20;
b = 12 * pi * t - 40;
c = 15 * pi * t + 60;
A = rewrite(8 + 6*cos(a) - 3*cos(b) + 10 *sin(c) ,'exp')
AE = expand(A)

figure
fplot(real(AE))
hold on
fplot(imag(AE))
hold off
grid
legend('Re','Im')

Ax = gca;                                                   % Define Axes Handle
Lines = Ax.Children;                                        % Get Line Handles
t1 = Lines(1).XData;                                        % Imaginary Part ‘x’ Value
t2 = Lines(2).XData;                                        % Real Part ‘x’ Value
y1 = Lines(1).YData;                                        % Imaginary Part ‘y’ Value
y2 = Lines(2).YData;                                        % Real Part ‘y’ Value

figure
stem(t2, y2, 'MarkerSize',2)
hold on
stem(t1, y1, 'filled', 'MarkerSize',5)
hold off
legend('Re','Im')
xlim([-0.05 0.05])                                          % View Details Near Origin (Optional)

.