function foh(y,alpha,Ts)% plot the output of fractional-order hold% % input: y - discrete signal vector as input signal to a fractional %            order hold%        alpha - 0 <= alpha <= 1, hold characteristics%        Ts = sampling period%%%%%%%%%%%%%%%%%%%%% foh.m %%%%%%%%%%%%%%%%%%%%%%   Discrete-Time Control Problems using        %%       MATLAB and the Control System Toolbox   %%   by J.H. Chow, D.K. Frederick, & N.W. Chbat  %%         Brooks/Cole Publishing Company        %%                September 2002                 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%n = length(y);% first point - need special logic% it is always assumed that the -1 point is zero%figureplot([-1 0]*Ts,[0 0])hold on plot([0 0]*Ts,[0 y(1)])plot(0,y(1),'o')yfoh(2) = y(1)+y(1)*alpha;plot([0 1]*Ts,[y(1) yfoh(2)])disp('<< press space bar to continue >>'), pausefor ii = 2:n  plot([ii-1 ii-1]*Ts,[yfoh(ii) y(ii)])  plot((ii-1)*Ts,y(ii),'o')  yfoh(ii+1) = y(ii)+(y(ii)-y(ii-1))*alpha;  plot([ii-1 ii]*Ts,[y(ii) yfoh(ii+1)])  disp('<< press space bar to continue >>'), pauseendtitle('Output of Fractional Order Hold')xlabel('Time (k*Ts)')ylabel('Amplitude')hold off %%%%%%%%%%