/usr/share/octave/packages/signal-1.3.2/tripuls.m is in octave-signal 1.3.2-1+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 | ## Copyright (C) 2001 Paul Kienzle <pkienzle@users.sf.net>
##
## This program is free software; you can redistribute it and/or modify it under
## the terms of the GNU General Public License as published by the Free Software
## Foundation; either version 3 of the License, or (at your option) any later
## version.
##
## This program is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
## details.
##
## You should have received a copy of the GNU General Public License along with
## this program; if not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {@var{y} =} tripuls (@var{t})
## @deftypefnx {Function File} {@var{y} =} tripuls (@var{t}, @var{w})
## @deftypefnx {Function File} {@var{y} =} tripuls (@var{t}, @var{w}, @var{skew})
##
## Generate a triangular pulse over the interval [-w/2,w/2), sampled at
## times t. This is useful with the function pulstran for generating a
## series pulses.
##
## skew is a value between -1 and 1, indicating the relative placement
## of the peak within the width. -1 indicates that the peak should be
## at -w/2, and 1 indicates that the peak should be at w/2.
##
## Example:
## @example
## @group
## fs = 11025; # arbitrary sample rate
## f0 = 100; # pulse train sample rate
## w = 0.3/f0; # pulse width 3/10th the distance between pulses
## auplot(pulstran(0:1/fs:4/f0, 0:1/f0:4/f0, 'tripuls', w), fs);
## @end group
## @end example
##
## @seealso{pulstran}
## @end deftypefn
function y = tripuls (t, w = 1, skew = 0)
if nargin<1 || nargin>3,
print_usage;
endif
y = zeros(size(t));
peak = skew*w/2;
try wfi = warning("off", "Octave:fortran-indexing");
catch wfi = 0;
end_try_catch
unwind_protect
idx = find(t>=-w/2 & t <= peak);
if (idx) y(idx) = ( t(idx) + w/2 ) / ( peak + w/2 ); endif
idx = find(t>peak & t < w/2);
if (idx) y(idx) = ( t(idx) - w/2 ) / ( peak - w/2 ); endif
unwind_protect_cleanup
warning(wfi);
end_unwind_protect
endfunction
%!assert(tripuls(0:1/100:0.3,.1), tripuls([0:1/100:0.3]',.1)');
%!assert(isempty(tripuls([],.1)));
%!demo
%! fs = 11025; # arbitrary sample rate
%! f0 = 100; # pulse train sample rate
%! w = 0.5/f0; # pulse width 1/10th the distance between pulses
%! subplot(211);
%! x = pulstran(0:1/fs:4/f0, 0:1/f0:4/f0, 'tripuls', w);
%! plot([0:length(x)-1]*1000/fs, x);
%! ylabel("amplitude"); xlabel("time (ms)");
%! title("graph shows 5 ms pulses at 0,10,20,30 and 40 ms");
%! subplot(212);
%! x = pulstran(0:1/fs:4/f0, 0:1/f0:4/f0, 'tripuls', w, -0.5);
%! plot([0:length(x)-1]*1000/fs, x);
%! ylabel("amplitude"); xlabel("time (ms)");
%! title("graph shows 5 ms pulses at 0,10,20,30 and 40 ms, skew -0.5");
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