generating/plotting aperiodic functions

Hey guyssss,

Can someone explain to me how I can define an aperiodic square function in MATLAB? This is the code I have for time:

TimeStep = 0.0001*2*pi;                              %time increment
Time.Start = 0;                               %time interval starting time
Time.End = 10*2*pi;                                %time interval ending time

Time = Time.Start:TimeStep:Time.End;

I want to be able to change the width and amplitude of the function. Any help would be greatly appreciated :)

Answer 1

[Fangjun Jiang]

f below will be your function.

f=@(t,StartTime,EndTime,Amplitude) Amplitude*and(StartTime<t,t<EndTime);

To test it out:

t=-1:0.1:5;
y=f(t,0.3,3.6,1.3);
plot(t,y);grid on;

[Sarah]

Thanks for the feedback!

I have an additional question...

Based on the coding for time that I provided above, could I modify your code to simply make it:

f = @(Time,Amplitude); %function defined

TimeStep = 0.0001*2*pi; %time increment

Time.Start = 0; %time interval starting time

Time.End = 10*2*pi; %time interval ending time

Time = Time.Start:TimeStep:Time.End;

Amplitude = 1;

y = f(Time,Amplitude)

plot(Time,y); grid on;

[Fangjun Jiang]

I guess I need your clarification. What are Time.Start and Time.End, the start/end time of your signal or the square? What is the "square function" that you are looking for? PWM?

[Sarah]

Time.Start represents the beginning of my sinusoidal signal. Time.End represents the end of my sinusoidal signal.

I want to add the aperiodic square, so just one square, to that sinusoidal signal. So essentially, at some point in the sinusoidal signal, you will see a jump to a different amplitude as a result of the square being added.

[Fangjun Jiang]

Okay, then what is the start/end time of the square?

[Sarah]

It can be anywhere within the duration of the sinusoidal signal. I can change those parameters later, i just want the square to occur within the time duration of the signal.

[Fangjun Jiang]

In the f() defined in my code, the StartTime and EndTime refer to the start/end time of the square. You can put the start/end time of your signal in the time vector.

t=(0:0.0001:10)*2*pi;

y=f(t,30,50,1.3);