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matlab: auto regressive model update, use error code to return status

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Signed-off-by: Thorsten Liebig <thorsten.liebig@gmx.de>
This commit is contained in:
Thorsten Liebig 2012-12-09 22:05:00 +01:00
parent c3058a4c0c
commit 68a24f3a9c
1 changed files with 51 additions and 9 deletions
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60
matlab/AR_estimate.m
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@ -1,8 +1,8 @@
function [val_ar t_ar f_val_ar] = AR_estimate( t, val, freq, nu, mu, expand_factor)
% [val_ar t_ar f_val_ar] = AR_estimate( t, val, freq, < nu, mu, expand_factor >)
function [val_ar t_ar f_val_ar EC] = AR_estimate( t, val, freq, nu, mu, expand_factor)
% [val_ar t_ar f_val_ar EC] = AR_estimate( t, val, freq, < nu, mu, expand_factor >)
%
% apply autoregressive signal model to improve dft results
%
%
% t : time vector
% val : time domain values
% freq : frequency vector for dft
@ -12,15 +12,37 @@ function [val_ar t_ar f_val_ar] = AR_estimate( t, val, freq, nu, mu, expand_fact
% mu : number of timesteps to train the model (default 3*nu)
% expand_factor : increase signal length by this factor (default 5)
%
%
% return values:
% val_ar: AR estimated time signal
% t_ar: time vector
% f_val_ar: FD transformed AR estimated signal
% EC: error code
% 0 --> no error
% 1 --> input error: t and val mismatch
% 2 --> input error: mu has to be larger than 2*nu
% 3 --> inout error: expand_factor has to be larger than 1
% 10 --> AR error: signal is to short for AR estimate --> decrease AR order
% 11 --> AR error: estimated signal appears to be unstable --> use a different mu
%
% openEMS matlab interface
% -----------------------
% Author: Thorsten Liebig, 2011
%
% See also ReadUI, DFT_time2freq
EC = 0;
val_ar = [];
t_ar = [];
f_val_ar = [];
if numel(t) ~= numel(val)
error 'numel(t) ~= numel(val)'
if (nargout<4)
error 'numel(t) ~= numel(val)'
else
EC = 1;
return
end
end
if (nargin<4)
@ -34,11 +56,21 @@ if (nargin<6)
end
if (mu<=2*nu)
error 'mu should be larger than 2*nu'
if (nargout<4)
error 'mu has to be larger than 2*nu'
else
EC = 2;
return
end
end
if (expand_factor<=1)
error 'expand_factor must be larger than 1'
if (nargout<4)
error 'expand_factor has to be larger than 1'
else
EC = 3;
return
end
end
dt = t(2)-t(1);
@ -46,7 +78,12 @@ dt = t(2)-t(1);
M = numel(t);
if (M<0.6*mu)
error 'signal is to short for AR estimate --> decrease AR order'
if (nargout<4)
error 'signal is to short for AR estimate --> decrease AR order'
else
EC = 10;
return
end
end
for n=1:mu-nu
@ -67,7 +104,12 @@ for k=M:expand_factor*M
end
if (max(val_ar(M:end)) > max(val))
error 'estimated signal appears to be unstable --> use a larger mu'
if (nargout<4)
error 'estimated signal appears to be unstable --> use a different mu'
else
EC = 11;
return
end
end
f_val_ar = DFT_time2freq(t_ar, val_ar, freq);