Hi, everyone! i need help to make this , instead of getting a matrix FTTx ( 4x8) i need to get a column vector (1x32) with the same values but i iam not able to do it , thank you

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mina massoud 2019-5-9

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https://ww2.mathworks.cn/matlabcentral/answers/461178-hi-everyone-i-need-help-to-make-this-instead-of-getting-a-matrix-fttx-4x8-i-need-to-get-a-co

编辑： dpb 2019-5-9

Lx=20;
N=4;
P=8;
L=2;
xBuff=zeros(N,1);
b=0.5; 
x  = filter(sqrt(1-b^2),  [1 -b],   (1/(sqrt(4)))*(randn(Lx,1)) );  
FFTX = zeros(N,P);   %%%%%%% FFTX = zeros(N*P,1);
 for k = 1 : L : 20   % k=1 ,2,3 .............. etc
        nn = k : k + L - 1; %1:2 , 2:3 , 3:4 ; 4:5.............etc
        xBuff(1 : N, :) = [ xBuff(L+1 : N, : ) ; x(nn, :) ];
        FFTX(:,2:P) = FFTX(:,1:P-1); 
        FFTX(:,1) = fft(xBuff);
 end

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mina massoud 2019-5-9

编辑：dpb 2019-5-9

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% this is my code but the answer is not the same , i don't know why

Lx=20;
N=4;
P=8;
L=2;
xBuff=zeros(N,1);
b=0.5; 
x  = filter(sqrt(1-b^2),  [1 -b],   (1/(sqrt(4)))*(randn(Lx,1)) );  
FFTX = zeros(N*P,1);
 for k = 1 : L : 20  % BlkSize = KK*F.L,   KK integer
        nn = k : k + L - 1; %1:2 , 2:3 , 3:4 ; 4:5.............etc
        xBuff(1 : N, :) = [ xBuff(L+1 : N, : ) ; x(nn, :) ];
        %FFTX(:,2:P) = FFTX(:,1:P-1); 
        FFTX(2:P,1) = FFTX(1:P-1,1);
        FFTX(1:4,1) = fft(xBuff);
 end