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annotate m-toolbox/classes/+utils/@math/fq2ri.m @ 0:f0afece42f48

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Import.
author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
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f0afece42f48 Import.
Daniele Nicolodi <nicolodi@science.unitn.it>
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1 % FQ2RI Convert frequency/Q pole/zero representation into real
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Daniele Nicolodi <nicolodi@science.unitn.it>
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2 % and imaginary conjugate pairs.
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Daniele Nicolodi <nicolodi@science.unitn.it>
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3 %
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Daniele Nicolodi <nicolodi@science.unitn.it>
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4 % [G,ri]= fq2ri(f0, Q)
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Daniele Nicolodi <nicolodi@science.unitn.it>
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5 %
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Daniele Nicolodi <nicolodi@science.unitn.it>
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6 % M Hewitson 26-01-07
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Daniele Nicolodi <nicolodi@science.unitn.it>
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7 %
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Daniele Nicolodi <nicolodi@science.unitn.it>
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8 % $Id: fq2ri.m,v 1.3 2008/10/24 09:40:19 hewitson Exp $
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Daniele Nicolodi <nicolodi@science.unitn.it>
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9 %
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Daniele Nicolodi <nicolodi@science.unitn.it>
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10 function [G,ri]= fq2ri(f0, Q)
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11
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Daniele Nicolodi <nicolodi@science.unitn.it>
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12 if(nargin==0)
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Daniele Nicolodi <nicolodi@science.unitn.it>
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13 disp('usage: ri = fq2ri2(f0, Q)')
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Daniele Nicolodi <nicolodi@science.unitn.it>
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14 return
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Daniele Nicolodi <nicolodi@science.unitn.it>
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15 elseif(nargin==1 || nargin==2 && isnan(Q))
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Daniele Nicolodi <nicolodi@science.unitn.it>
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16 ri = -((2*pi*f0));
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Daniele Nicolodi <nicolodi@science.unitn.it>
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17 elseif(nargin==2 && Q>=0)
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Daniele Nicolodi <nicolodi@science.unitn.it>
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18 if Q < 0.5
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Daniele Nicolodi <nicolodi@science.unitn.it>
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19 disp('!!! Q < 0.5! Splitting to two real poles;')
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Daniele Nicolodi <nicolodi@science.unitn.it>
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20 a = 2*pi*f0/(2*Q)*(1+sqrt(1-4*Q^2));
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Daniele Nicolodi <nicolodi@science.unitn.it>
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21 b = 2*pi*f0/(2*Q)*(1-sqrt(1-4*Q^2));
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Daniele Nicolodi <nicolodi@science.unitn.it>
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22 ri = [a b];
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Daniele Nicolodi <nicolodi@science.unitn.it>
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23 elseif Q == 0.5
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Daniele Nicolodi <nicolodi@science.unitn.it>
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24 disp('!!! Q = 0.5! Returning one real pole;')
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Daniele Nicolodi <nicolodi@science.unitn.it>
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25 w0 = 2*pi*f0;
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Daniele Nicolodi <nicolodi@science.unitn.it>
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26 re = w0/(2*Q);
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Daniele Nicolodi <nicolodi@science.unitn.it>
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27 ri = [re];
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Daniele Nicolodi <nicolodi@science.unitn.it>
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28 else
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Daniele Nicolodi <nicolodi@science.unitn.it>
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29 w0 = 2*pi*f0;
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Daniele Nicolodi <nicolodi@science.unitn.it>
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30 re = w0/(2*Q);
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Daniele Nicolodi <nicolodi@science.unitn.it>
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31 im = w0*sqrt(1-1/(4*Q^2));
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Daniele Nicolodi <nicolodi@science.unitn.it>
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32 tri = complex(re,im);
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Daniele Nicolodi <nicolodi@science.unitn.it>
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33 ri = [tri; conj(tri)];
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Daniele Nicolodi <nicolodi@science.unitn.it>
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34 end
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35 end
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36
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37 end
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Daniele Nicolodi <nicolodi@science.unitn.it>
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38 % END