jens
4a3bf9eea3
git-svn-id: http://moon:8086/svn/software/trunk/projects/GnuRadio@432 b431acfa-c32f-4a4a-93f1-934dc6c82436
94 lines
2.0 KiB
Matlab
94 lines
2.0 KiB
Matlab
## Copyright (C) 2019 Jens
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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, but
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## 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
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## <https://www.gnu.org/licenses/>.
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## -*- texinfo -*-
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## @deftypefn {} {@var{retval} =} peak_detect (@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 <jens@orion>
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## Created: 2019-05-20
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function retval = peak_detect ()
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N = 1024
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Nh = N/2;
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kn = 0.1
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close all;
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figure
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pa = 0.3;
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d_max = 30;
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s = zeros(1, Nh);
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a = zeros(1, Nh);
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Xm = zeros(1, Nh);
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Xs = zeros(1, Nh);
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peak_count = zeros(1, Nh);
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am = 0.1;
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as = 0.9;
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for k=1:64
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% Peak generation
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f = fix(N/2*rand());
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k = f + 1;
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if (rand() < pa)
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if (s(k) == 0)
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a(k) = 1.0;
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s(k) = fix(d_max*rand());
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end
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end
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x = kn*randn(1, N);
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for n = 1:Nh
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if s(n) > 0
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s(n) = s(n) - 1;
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x = x + a(n)*cos(2*pi*n*(0:N-1)/N);
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end
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end
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X = abs(fft(x))/sqrt(N);
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X = X(1:Nh);
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X = 10*log10(X.*X);
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% Peak detection
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Xs = (1-as)*Xs + as*X;
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Xm_gate = Xs > (10+Xm);
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peak_count = Xm_gate.*peak_count + Xm_gate;
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peak = peak_count > 1;
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% Update Xm at no-peak bins
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Xm = (1-peak) .* ((1-am)*Xm + am*X) + peak.*Xm;
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% Output
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marker_X = find(peak ~= 0);
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marker_Y = X.*peak;
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subplot(2, 1, 1)
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plot(1:Nh, X, marker_X, marker_Y(marker_X), '+'); grid; axis([0, Nh, -60, 40]);
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subplot(2, 1, 2)
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plot(1:Nh, Xs, 1:Nh, Xm); grid; axis([0, Nh, -60, 40]);
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pause(1/30);
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end
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function s = matchedFilter(N, B)
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n2 = (N-1)/2
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n = (0:N-1)-n2
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s = sinc(n/B)
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endfunction
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endfunction
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