How to plot the real and imaginary parts of a signal using subplot function.

I am new to Matlab and my Signals and Systems teach threw a tough lab at us that involves plotting the real and imaginary parts of a signal on the same plot but only using the subplot function, anything helps.

[Sindar]

What have you tried? Provide some example code

[Hayden Bingham]

t = 0:0.1:10;

a = cos(pi./6*t);

subplot (2,1,1);

plot(a);

b = sin(pi./6*t);

subplot (2,1,2);

plot(b);

Answer 1

[Sindar]

Ok, you're pretty much there already. Just a few things:

• plot t on the x-axes
• title the plots

t = 0:0.1:10;
a = cos(pi./6*t);
subplot (2,1,1);
plot(t,a);
% \pi appears as the symbol
title('cos(\pi/6*t)')
% similar for b

Additionally, you could use the real/imag functions to define a and b:

% I use 1i as the imaginary number. That way, if you redefine i (e.g., in a loop), it will error
x=exp(1i*pi./6*t);
a=real(x);
b=imag(x);

Answer 2

[Hayden Bingham]

Thank you so much, from what I gathered from the write-up we weren't supposed to use real and imag, but I will keep it in mind.

[Sindar]

I believe the problem is saying that you can't use real/imag to create the titles, but that it is ok to use it for the data

Answer 3

[Tabraiz Khan]

Write MATLAB code to plot the magnitude and phase of the following complex exponential function. Also plot the real and imaginary parts of the given signal using subplot command.

z=300 ej(4ᴨt-0.75)

[Sindar]

In the future, please don't ask additional questions as an Answer. But:

• abs(z) will give you the magnitude
• angle(z) will give you the phase
• everything else as in my answer above