jens
f59fb8f67d
git-svn-id: http://moon:8086/svn/matlab/trunk@100 801c6759-fa7c-4059-a304-17956f83a07c
157 lines
3.1 KiB
Matlab
Executable File
157 lines
3.1 KiB
Matlab
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} =} garage (@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: 2018-12-06
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function bits = garage (varargin)
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params = struct ('numSamplesPerSym', 4, 'with_filter', 0, 'k_noise', 0.04);
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units = struct ('numSamplesPerSym', 'sps', 'with_filter', '', 'k_noise', '');
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% Parse parameters
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names = fieldnames(params);
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for k=1:nargin-1,
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for n=1:length(names),
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if strcmpi(varargin{k}, names{n})
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params.(names{n}) = varargin{k+1};
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end
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end
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end
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print_parameters(params, units)
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k_n = params.k_noise; % NOise
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k_s = 1.0; % Sym
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numSamplesPerSym = params.numSamplesPerSym;
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baud = 9600;
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fs = baud * numSamplesPerSym;
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numSyms = 50;
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numBursts = 3;
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numSymsPauseBetweenBurst = 50;
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syms = rand(numSyms, 1) > 0.5;
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bit = 0;
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syms_m = [];
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% Line coding
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for n=1:numSyms,
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if syms(n) == 1
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syms_m = [syms_m bit];
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bit = not(bit);
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syms_m = [syms_m bit];
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bit = not(bit);
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else
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syms_m = [syms_m bit];
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syms_m = [syms_m bit];
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bit = not(bit);
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end
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end
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% Upconvert
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x = [];
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for k=1:numBursts
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for n=1:2*numSyms,
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for m=1:numSamplesPerSym,
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x = [x syms_m(n)];
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end
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end
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x = [x zeros(1, numSymsPauseBetweenBurst*numSamplesPerSym)];
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end
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% Channel
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[b,a] = butter(2, baud/fs);
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if params.with_filter
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x = filter(b, a, x);
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end
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y = k_s*x + k_n*randn(1, length(x));
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y = wavread('seq.wav');
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N = length(y);
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n = 1:N;
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bit = 0;
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count = numSamplesPerSym;
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smp = [];
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smp_n = [];
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bits = [];
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% Receive
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state = "Init";
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peakFindCount = 10;
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v_min = 0;
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v_max = 0;
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for n=1:N
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state_next = state;
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v_thr = (v_max - v_min) / 2;
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if y(n) < v_min
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v_min = y(n);
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elseif y(n) > v_max
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v_max = y(n);
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end
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v_min = v_min + 1e-5*(v_thr - v_min);
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v_max = v_max - 1e-5*v_max;
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if strcmp(state, "Init")
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state_next = "Decode";
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elseif strcmp(state, "Decode")
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bit_curr = y(n) > v_thr;
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if (bit ~= bit_curr)
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count = fix(numSamplesPerSym/2);
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bit = bit_curr;
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end
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if count > 0
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count = count - 1;
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else
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count = numSamplesPerSym-1;
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smp = [smp y(n)];
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smp_n = [smp_n n];
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bits = [bits bit_curr];
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end;
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_cnt(n) = count;
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end
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_v_tr(n) = v_thr;
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if ~strcmp(state, state_next)
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fprintf(stdout, "Change state: %s => %s\n", state, state_next);
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state = state_next;
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end
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end
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bits = bits';
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n = 1:N;
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% Plot
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subplot(2, 1, 1)
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plot(n, y, '-o', smp_n, smp, 'rx', n, _v_tr, 'y'); grid;
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subplot(2, 1, 2)
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plot(n, _cnt); grid;
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endfunction
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