drawing a triangular wave

hey guys, what would be the best way to draw a triangular wave?

I just need one triangular wave so my attempt was to draw the left side of the peak of something like y = 2x -8

and right side y = -2x + 8 or something and combine the two, but then I dont know how to make that into one function or graph?

Answer 1

[Salaheddin Hosseinzadeh]

Hi Soloby,

You just asked a question on fuzzy logic, I assume this is in the same area!

Have you tried trimf or trapmf membership functions?

[soloby]

i just looked at the help trapmf

it states

        x = (0:0.1:10)';
        y1 = trapmf(x, [2 3 7 9]);
        y2 = trapmf(x, [3 4 6 8]);
        y3 = trapmf(x, [4 5 5 7]);
        y4 = trapmf(x, [5 6 4 6]);
        plot(x, [y1 y2 y3 y4]);
        set(gcf, 'name', 'trapmf', 'numbertitle', 'off');

what if i just need 1 symmetric triangular wave?

[Salaheddin Hosseinzadeh]

Soloby

You can either use trimf or!!!

do it like this

y1 = trapmf(x,[2 3 3 9]);

To of the numbers in the middle that defines the trapmf should be the same, which indicates the apex of your triangle

[soloby]

I have tried this.

x = 0:10:0.1; f1 = trapmf(x, [2 7 7 9]); f2 = trapmf(x, [2 9 9 18]); plot(x, f1, x, f2)

nothing seems to be showing up in my graph, though? do you know why

[Salaheddin Hosseinzadeh]

you made a mistake defining x

x = 1:0.1:10

not

x = 0:10:0.1 % this is wrong

[soloby]

you're completely right. thank you. I'll ask more on the other question we've been threading. thanks!

Answer 2

[Image Analyst]

See my attached demo

% Creates triangle waves two ways, one using repmat() and 
% one using sawtooth() from the Signal Processing Toolbox.