## Copyright (C) 2018 Jens Ahrensfeld
## 
## 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{retval} =} interpol_eval (@var{input1}, @var{input2})
##
## @seealso{}
## @end deftypefn

## Author: Jens Ahrensfeld <ahrensfeld@w2ess001vm>
## Created: 2018-11-21

function interpol_eval ()

N = 20;
n = (0:N-1);

f = 1;
x = cos(2*pi*f*n/N);

Ts = 0.75;

ii = 0;
ns = [];
while ii < (N-1)
	ns = [ns ii];
	ii = ii + Ts;
end

is = fix(ns);
fs = ns - is;
is = is + 1;

xs = (1-fs).*x(is) + fs.*x(is+1);

plot(n, x, '-*', ns, xs, 'rx'); grid;

endfunction