endif
  
  if nargin<5
    x_0 = zeros(n_x,1);
  endif
  
  if nargin<6
    p_c.N = 10;
  endif

  if nargin<7
    p_o.sigma = 1e-1;
  endif

  if !struct_contains(p_c,"delta_ol")
    p_c.delta_ol = 1.0;	# OL sample interval
  endif
  
  if !struct_contains(p_c,"T")
    p_c.T = 10.0;			# Last time point.
  endif

  if !struct_contains(p_c,"augment")
    p_c.augment = 1;		# Augment basis funs with contand
  endif
  
  if !struct_contains(p_c,"Method")
    p_c.Method = "lq";
  endif

  if struct_contains(p_c,"Method")
    if strcmp(p_c.Method,"lq") 
      p_c.Q = eye(n_y);
      p_c.R = (0.25^2)*eye(n_u);
      p_c.n_U = n_x;
    elseif strcmp(p_c.Method,"original");
      if !struct_contains(p_c,"A_w")
	p_c.A_w = 0;
      endif
      if !struct_contains(p_c,"A_u")
	p_c.n_U = n_x;
	a_u = 2.0;
	p_c.A_u = laguerre_matrix(p_c.n_U,a_u);
	if p_c.augment		# Put in constant term
	  A_u = ppp_aug(0,A_u);
	endif
      endif
    else
      error(sprintf("Method %s not recognised", p_c.Method));
    endif
  endif
  

  y = [];
  u = [];
  t = [];
  y_e = [];
  t_e = [];
  e_e = [];
  tick = time;

  for i=1:I

    i
    tim=time;			# Timing
    if Simulate			# Exact simulation 
      t_sim = [1:p_c.N]*dt;	# Simulation time points
      [yi,ui,xsi] = ppp_ystar(A,B,C,D,x,p_c.A_u,U,t_sim); # Simulate
      x = xsi(:,p_c.N);	# Current state (for next time)
      y_now = yi(:,p_c.N);	# Current output
      ti  = [(i-1)*p_c.N:i*p_c.N-1]*dt; 
    else			# The real thing
      to_rt(U');		# Send U
      data = from_rt(p_c.N);	# Receive data
      [yi,ui,ti] = convert_data(data); # And convert from integer format

      y_now = yi(:,p_c.N);	# Current output
    endif
    sample_time = (time-tim)/p_c.N
    tim = time;
    ## Observer
    if strcmp(p_o.method, "intermittent")
      [x_est y_est e_est] = ppp_int_obs \
	  (x_est,y_now,U,A,B,C,D,p_c.A_u,p_c.delta_ol,L);
    elseif strcmp(p_o.method, "continuous")
      Ui = U;			# U at sub intervals
      for k = 1:p_c.N
	[x_est y_est e_est] = ppp_int_obs \
	    (x_est,yi(:,k),Ui,A,B,C,D,p_c.A_u,dt,L);
	Ui = A_ud'*Ui;
	y_e = [y_e; y_est'];
	e_e = [e_e; e_est];
      endfor
    endif
    
    ##Control
    U = K_w*w - K_x*x_est;

    ## Save data

    t = [t;ti'];
    y = [y;yi'];
    u = [u;ui'];







    if strcmp(p_o.method, "intermittent")
      y_e = [y_e; y_est'];
      e_e = [e_e; e_est];
      t_e = [t_e; (i*p_c.N)*dt];
    endif

    overrun = time-tim
  endfor			# Main loop



  if strcmp(p_o.method, "continuous")
    t_e = t;
  endif
  
  
  sample_interval = (time-tick)/(I*p_c.N)

  ## Put data on file (so can use for identification)
  filename = sprintf("%s_ident_data.dat",Name);
  eval(sprintf("save -ascii %s t y u",filename));


#   ## Plot
#   gset nokey
#   title("");
#   boxed=0;
#   monochrome=1;
#   grid;
#   xlabel("t");

#   ylabel("y");
#   figure(1);plot(t,y, t_e,y_e,"+");

#   ylabel("u");
#   figure(2);plot(t,u);

#   ylabel("e");
#   figure(3);plot(t_e,e_e);


endfunction