How to generate a sawtooth wave

I get the graph i want.But the amplitude is from -10 to 10. Can i know how can i change it to 0 to 10 and keep the same graph?

Here is what i tried so far: T=2*4; Fs=1000; dt = 1/Fs; t = 0:dt:T-dt; x =-10*sawtooth(2*pi*t);

plot(t,x) grid on

Answer 1

[Star Strider]

You only need to make 2 changes:

T=2*4;
Fs=1000;
dt = 1/Fs;
t = 0:dt:T-dt;
x = sawtooth(2*pi*t);                   % <— REMOVE THE ‘-10’ HERE
x = (x + 1)*5;                          % <— ADD THIS LINE

plot(t,x)
grid on

[Tze Chwen Lim]

Thank you but can i know why i need to add that (x+1)*5? And the time need to be in ms so when i multiplies the time with 10^-3 , the graph goes wrong why would this happen?

[Star Strider]

My pleasure.

The default output amplitude of the sawtooth function is ±1, so adding 1 produces an amplitude of 0 to +2. Multiplying that by 5 produces the 0 to +10 amplitude you want.

Your time already appears to be in milliseconds because of the way you defined ‘dt’. You do not need to multiply it by anything.

You can label the x-axis as:

xlabel('Time (ms)')

or if you want to label it in seconds, this works:

plot(t,x)
grid on
xt = get(gca, 'XTick');
set(gca, 'XTick',xt, 'XTickLabel',xt*1E-3)
xlabel('Time (seconds)')

Here, you simply re-label the tick labels. Everything else remains the same.

Answer 2

[Boris Adum]

You can also write a function that would generate that wave. If you name your amplitude A, and the width of one tooth W then you can write two functions.

• If you want the function to go from 0 to A

%define amplitude
A = 10; %set your own value
%define width of one tooth
W=5; %set your own value

syms x y;
y=A/W*(x-(W*fix(x/W)))

%plot the function over an interval
fplot(y,[0,3*W]) %set your own limits for ploting

• If you want the function to go from -A to A

clear %clear old variables if needed
A=10; %amplitude limits of the sawtooth wave -A to A
W=5; %witdh/step of the sawtooth wave
syms x y;
y=((2*A)/W)*(x-(fix(x/W)*W))-A
fplot(y,[0,5*W]) %Plots five teeth

Answer 3

[Sohan Das]

T=2*4;

Fs=1000;

dt = 1/Fs;

t = 0:dt:T-dt;

x = sawtooth(2*pi*t); % <— REMOVE THE ‘-10’ HERE

x = (x + 1)*5; % <— ADD THIS LINE

plot(t,x)

grid on

Answer 4

[Sohan Das]

T=2*4;

Fs=1000;

dt = 1/Fs;

t = 0:dt:T-dt;

x = sawtooth(2*pi*t);

x = (x + 1)*5;

plot(t,x)

grid on