function [re,im,w,FocusInfo,sdre,sdim] = nyquistresp_(sys,wspec)
% Compute the real and the imaginary parts of frequency response
% Compute frequency response (grade = 1)
% (magnitude in abs value, phase in radians)

% Copyright 1986-2014 The MathWorks, Inc.
[m,p,w,FocusInfo] = magphaseresp_(sys,1,wspec);
re = m .* cos(p);  im = m .* sin(p);
sdre = []; sdim = []; % default values for models with no covariance