function [out] = ramp_gen(gain,offset,freq,time)
% This function computes the ramp signal
% Inputs:  
%         gain = Gain to output
%         offset = Offset to output
%         freq = Frequency (Hz)
%         time = Time (sec)
% Output:
%         out = Ramp signal varying between 0 and 1 for gain=1 and offset=0

T_ramp = 1/abs(freq);          % Period of ramp signal (sec)
time_rmp = rem(time,T_ramp);   % time for computing the output (sec)

if freq > 0     % ramp from 0 to 1 if freq > 0 (for gain=1, offset=0)
   out = gain*(1/T_ramp)*time_rmp + offset;
else            % ramp from 1 to 0 if freq < 0 (for gain=1, offset=0)
   out = gain*(-(1/T_ramp)*time_rmp+1) + offset;
end