Multi sine waves function

Hello, right now I don't know how to create a multi sinus function with frequency from 1kHz to 2 kHz, with Amplitude varies from 0.25 to 1, in time from -2.5 to 2.5 second. I have tried with a loop 'for' but the problem is matrice t and f can't multiply with each other because of size.

for f = 1000:200:2000
  A(n)  = 1:-0.75/(length(f)-1):0.25;    
  V(n)  = A(n)*sin(2*pi*f.*t + phi);
end

can someone help me with this?

[Kanard]

can anyone check if what I wrote here is correct or not.

ts = 1/100;
t = -0.25:ts:0.25;
f = 400:200:3000;
A = 1:-0.75/(length(f)-1):0.25;
V = 0;
phi = rand(1,14);
for i = 1:14
  V = V + A(1,i)*sin(2*pi*f(1,i)*t + phi(1,i));
  plot(t,V(1,:));
  hold on
end

Answer 1

[Star Strider]

I’m not certain what result you want.

Your posted code doesn’t show any oscillations when I run it. I would change the argument of the sin function to divide by the number of elements of ‘t’ in order to show the oscillations:

V = V + A(1,i)*sin(2*pi*f(1,i)*t/numel(t) + phi(1,i));

Beyond that, I have no suggestions.

[Kanard]

Hello, thanks for your reply, what I want is a function, which is a sum of many other sinusoidal signals, which frequencies and Amplitudes are in the range above. I tried to assign F and A to matrices and calculate each signal then plot all of them into a single figure. However i'm not sure if this is correct or not.

[Star Strider]

My pleasure.

Your code calculates and plots the evolving sum of all the waveforms, so if that’s what you want to do, it’s working.