function y = sigmoid(x,p)

% y = diffsigmoid(x,[a c])
%
% Input Variables
%   x - the time points
%   a - slope 
%   c - inflection point
%
% Output Variables
%   y - output signal
%
% Description
%   Generates  a sigmoids as a time series.

% Created     
%   4/21/2006, Richard J. Povinelli, Marquette University

% This software is released under the terms of the GNU General
% Public License (http://www.gnu.org/copyleft/gpl.html).

% Modified

a = p(1);
c = p(2);

y = 1 ./ (1 + exp(-a .* (x - c))); %formula for a sigmoid