jens
f59fb8f67d
git-svn-id: http://moon:8086/svn/matlab/trunk@100 801c6759-fa7c-4059-a304-17956f83a07c
99 lines
2.0 KiB
Objective-C
Executable File
99 lines
2.0 KiB
Objective-C
Executable File
## Copyright (C) 2018 Jens Ahrensfeld
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##
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## This program is free software; you can redistribute it and/or modify it
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## under the terms of the GNU General Public License as published by
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## the Free Software Foundation; either version 3 of the License, or
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## (at your option) any later version.
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##
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## This program is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License
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## along with this program. If not, see <http://www.gnu.org/licenses/>.
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## -*- texinfo -*-
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## @deftypefn {Function File} {@var{retval} =} im_eval (@var{input1}, @var{input2})
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##
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## @seealso{}
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## @end deftypefn
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## Author: Jens Ahrensfeld <ahrensfeld@w2ess001vm>
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## Created: 2018-10-22
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function s = im_eval ()
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s1 = sig_gen('lo', 'sine', [0 500], [0.0 1]);
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s2 = sig_gen('s1', 'sine', [0 100 500 900 1400], [0.0 0.5 1.0 0.5 0.25]);
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s = modulate(s1, s2);
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close all;
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plotSig(s);
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function s = sig_gen(name, type, freq, amp)
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peaks = [];
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switch type
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case 'sine'
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f = freq;
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a = amp;
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case 'rect'
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N = 10;
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f = [];
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a = [];
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k = 1;
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for n=1:N
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f = [f k*freq];
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a = [a amp/k];
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k = k + 2;
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end
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endswitch
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s = struct('name', name, 'f', f, 'a', a);
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endfunction
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function m = modulate(s1, s2)
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m = struct('name', sprintf("%s x %s", s1.name, s2.name), 'f', [], 'a', []);
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f = [];
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a = [];
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for i=1:length(s1.f)
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for j=1:length(s2.f)
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f1 = s1.f(i) - s2.f(j);
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f2 = s1.f(i) + s2.f(j);
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a = s1.a(i) * s2.a(j);
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m = addFreq(m, f1, a);
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m = addFreq(m, f2, a);
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end
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end
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endfunction
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function x = addFreq(x, f, a)
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found = 0;
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for i=1: length(x.f)
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if (x.f(i) == f)
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found = i;
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break;
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end
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end
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if (found > 0)
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x.a(found) = x.a(found) + a;
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elseif a ~= 0
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x.f = [x.f f];
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x.a = [x.a a];
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end
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endfunction
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function plotSig(s)
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stem(s.f, s.a, 'baseline', -10); grid; legend(s.name)
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endfunction
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endfunction
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