nk_to_nm.m

用于模拟时变非平稳的ARMA过程

function A= nk_to_nm(B)
% function A= nk_to_nm(B)
%   This file is part of the TFPM toolbox v1.0 (c)
%   [e-mail] and underlies the GPL.
% 
% The function 
% B[n, k], n= 0:N-1; k= -N/2:N/2-1. 
% is inverse Fourier transformed into the function 
% A[n, m], n= 0:N-1; m= -N/2:N/2-1 

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if(0)% TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST
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clear;%tfpm;
MAR  =   7;
LAR  =   5;
MMA  =   5;
LMA  =   3;
N    =  64;
re_im= 'i';
mo_no= 'm';
tfpm_file_gen;
%-------------
alpha= 1/2;
A0= alpharize(tvarma_impr(Amn, Bmn), 0, alpha);
B= nm_to_nk(A0);
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end;% TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST
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% Dimensions:
N= size(B, 1);

A= ifft([B(:, N/2+1:N) B(:, 1:N/2)].').';
A= [A(:, N/2+1:N) A(:, 1:N/2)];

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if(0)% TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST
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max(max(abs(A-A0)))
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end;% TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST
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