Mercurial > hg > ltpda
comparison m-toolbox/classes/@pz/cp2iir.m @ 0:f0afece42f48
Import.
| author | Daniele Nicolodi <nicolodi@science.unitn.it> |
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| date | Wed, 23 Nov 2011 19:22:13 +0100 |
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| -1:000000000000 | 0:f0afece42f48 |
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| 1 % CP2IIR Return a,b IIR filter coefficients for a complex pole designed using the bilinear transform. | |
| 2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 3 % | |
| 4 % DESCRIPTION: CP2IIR Return a,b IIR filter coefficients for a complex pole | |
| 5 % designed using the bilinear transform. | |
| 6 % | |
| 7 % CALL: [a,b] = cp2iir(p, fs) | |
| 8 % | |
| 9 % REMARK: This is just a helper function. This function should only be | |
| 10 % called from class functions. | |
| 11 % | |
| 12 % INPUT: p - pole object | |
| 13 % fs - the sample rate for the filter | |
| 14 % | |
| 15 % VERSION: $Id: cp2iir.m,v 1.7 2011/02/18 16:48:54 ingo Exp $ | |
| 16 % | |
| 17 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 18 | |
| 19 function varargout = cp2iir(varargin) | |
| 20 | |
| 21 p = varargin{1}; | |
| 22 fs = varargin{2}; | |
| 23 | |
| 24 f0 = p.f; | |
| 25 q = p.q; | |
| 26 | |
| 27 w0 = f0*2*pi; | |
| 28 w02 = w0^2; | |
| 29 | |
| 30 k = (q*w02 + 4*q*fs*fs + 2*w0*fs) / (q*w02); | |
| 31 b(1) = 1; | |
| 32 b(2) = (2*w02-8*fs*fs) / (k*w02); | |
| 33 b(3) = (q*w02 + 4*q*fs*fs - 2*w0*fs) / (k*q*w02); | |
| 34 | |
| 35 a(1) = 1/k; | |
| 36 a(2) = -2/k; | |
| 37 a(3) = -1/k; | |
| 38 a = a*-2; | |
| 39 | |
| 40 varargout{1} = a; | |
| 41 varargout{2} = b; | |
| 42 end | |
| 43 |