function g = er_shift(f,m)
% function g = er_shift(f,m)
%   Function to time-shift given transfer function coefficient vectors 
%   in struct F. M > 0 implies left-shift, M < 0 implies right-shift.
%
%   Author:  Evan Ruzanski, CU-Boulder, ECEN5632 MATLAB assignment, FA2004

% Unpack struct
num1 = f(1).tf_complete;
den1 = f(2).tf_complete;

% Time shift
if m < 0
    num2 = [zeros(1,-m) num1];
    den2 = [den1 zeros(1,-m)];
elseif m > 0
    num2 = [num1 zeros(1,m)];
    den2 = [zeros(1,m) den1];
else
    num2 = num1;
    den2 = den1;
end

% Repack
f(1).tf_complete = num2;
f(2).tf_complete = den2;
g = f;