decompose trigonometric signal

[ncomputinguae]

decompose signal

hello guys
i want to know how we can decompose for example
x=a1*sin(2*pi*f1*t)+a2*sin(2*pi*f2*t2)
i confuse that first find fft or dft which means
y[array of output]=fft or dft or... * x[array of input that here is x]
but i have question what is x , x is just one signal how we can find one array from x?
and after that what is important for us ?
how can we find ferequenses from that?
pleea help me i am very very confuse

 

[MHanif]

Hi ncomputinguae
Probably you are asking about MATLAB implementation.
First the input x=a1*sin(2*pi*f1*t)+a2*sin(2*pi*f2*t) is having time as independent variable.
Since you cannot work with continuous signals in Digital Computer, so you define a discrete signal say

t=0:0.01:10;

Now 't' is an array.
Like wise x=a1*sin(2*pi*f1*t)+a2*sin(2*pi*f2*t) is also an array.
Now you take fft of x which will result y which is also an array! Hope this explanation removes your confusion about array.

Secondly you asked about the frequency component in the signal. This can be found by observing the amplitude of each bin of the fft.