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Matlab

, x, var std:

v = var (x); %

sigma = std (x); %

Signal Processing Toolbox ( ). xcorr . , , . , x, :

R = xcorr(x) / length(x);

, . , , , .

Rplus = R(floor(length(R)/2):end);

length , floor .

, , /, . - :

w = [0:0.1:5];

Sw = [];

for i=1:length(w)

Sw(i) = sum(Rplus.* cos(w(i)*t));

end;

Sw = 2*T*Sw;

t , R plus , T . .* ( ) .

. ,

hamm = 0.54 + 0.46*cos(pi*t/max(t));

Rplus = Rplus.* hamm;

, .

.

N = 512; % ( )

w = 2* pi *[0: N /2] / N / T; %

Fw = T * fft (x, N); % F_X(w)

Sw = Fw.* conj (Fw) / N / T; % S_X(w)

Sw = Sw (1: N /2+1); %

. , , . . nextpow2, , . ( /):

dw = 0.5; %

N = 2* pi / dw / T; %

N = 2^ nextpow 2(N); %

. . ,

hamm = hamming(length(x));

scale = 1 / sqrt(0.54^2 + 0.46^2/2);

hamm = hamm * scale;

hamming Signal Porcessing Toolbox, .

Fw = T * fft (x.*hamm, N); % F_X(w)

.

 


[1] , 2 .

[2] , , - .



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