# Creating a piecewise sine function having different frequency components

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Jack Talaga on 19 May 2019
Hello,
I am brandnew in Matlab and i would like to generate a piecewise sine function with different frequency components. i.e. a signal at 1 kHz sampling frequency and having 100,200 and 300 Hz frequency components. I check the other topics but couldn't find a proper solution.
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John D'Errico on 19 May 2019
Please don't add an answer to an old question just to raise it up. You asked your own question anway.

Sulaymon Eshkabilov on 19 May 2019
Edited: Sulaymon Eshkabilov on 19 May 2019
Hi,
If I've understood your question correctly, this is what you are trying to create:
fs = 1e3; % Sampling frequency [Hz]
t = 0:1/fs:1; % Time space [0, 1] [sec]
f1 = 100;
f2 = 200;
f3 = 300;
S1 = sin(2*pi*f1*t);
S2 = sin(2*pi*f1*t);
S3 = sin(2*pi*f1*t);
Stotal = S1+S2+S3;
plot(t, Stotal)
Note that your fs is too small (it is better to have your fs = 10[kH]) for your generated frequency components of 100, 200, 300 Hz
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javeria noor on 10 Nov 2020
what to do if we want to multiply s1 and s2

Star Strider on 19 May 2019
Try this:
Fs = 1000;
t = linspace(0, 1, 1E+3)/Fs; % Time Vector (1 sec)
f = 100:100:300; % Frequency Vector
sm = sin(2*pi*f(:)*t*Fs)'; % Signal Matrix
sv = sm(:); % Signal Vector
tv = (0:numel(sv)-1/Fs)/Fs;
figure
plot(tv, sv)
grid
sound(sv, Fs) % Listen To The Result
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javeria noor on 10 Nov 2020
what if we want totake product of s1 and s2

Sulaymon Eshkabilov on 10 Nov 2020
There are two opts. One elementwise multiplication and the other is just product.
% (1) Elementwise:
S1S2_e = s1.*s2;
% (2) Just a product of two row matrix (vector) elements
S1S2_p = s1*s2';