frequency spectrum using fft function
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is the code is right for a question :
compute the frequency spectrum using fft function (512 points) and generate a 4_by_2 plot such as :
the first column displays the window function in time domain 0<=n<=M-1 , the second column displays the window function in frequency domain with the correct frequency scaling in [0,fs/2].
consider a sinusoidal mixture x(n) given as:
x(n)=A1sin(w1nTs+O1)+A2sin(w2nTs+O2)+v(n)
where A1=0.1,A2=1,w1=2ᴨ0.1,w2=2ᴨ0.15,Ts=1,O1,O2 distributed between [0,2ᴨ],v(n)is a zero-mean white Gaussian noise process of variance Q^2=0.01.
clear,clc,close all
% _ _ signal generation
A1= 0.1; % Amplitude 1
A2= 1; % amplitude 2
w1= 2*pi*0.1; % angular frequency 1
w2= 2*pi*1; % angular frequency 2
Ts= 1; % sampling time
N= 512; % no. of process samples to be generated
K= ; % no. of independent process realization
sgm= ; % standard deviation of the noise
n=repmat([0:N-1].',1,k)
phi1=repmat(rand(1,k)*2*pi,N,1) ; % random phase matrix 1
phi2=repmat(rand(1,k)*2*pi,N,1) ; % random phase matrix 2
x=A1*sin(w1*n*Ts+phi1)+A2*sin(w2*n*Ts+phi2)+sgm*randn(N,k) ; % resulting signal
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Answers (1)
Rick Rosson
on 3 Jan 2012
It looks like you have a good start. Here are some additional functions that will help complete the assignment:
>> doc fft
>> doc fftshift
>> doc abs
>> doc log10
>> doc rand
>> doc randn
>> doc figure
>> doc subplot
>> doc plot
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