ch11_b.m

来自「线性调频信号通过匹配滤波器的程序 还有一些simulink仿真模型」· M 代码 · 共 29 行

% Produce a state portrait for the SIMULINK model sysmdl_e
% using a quiver plot
h = 0.01 ; % Fixed step size
opts = simset('Solver','ode5','FixedStep',h) ;
x1 = -2.5:0.25:2.5 ;   % Set up the x1 and x2 grid
x2 = -2.5:0.25:2.5 ;
[nr,nc] = size(x1) ;  
x1m = zeros(nc,nc) ;  % Allocate space for the output vectors
x2m = x1m ;
for nx1 = 1:nc
  for nx2 = 1:nc
    opts = simset(opts,'InitialState',[x1(nx1),x2(nx2)]) ;
    [t,x,y] = sim('sysmdl_e',h,opts) ;
    dx1 = x(2,1)-x1(nx1) ;
    dx2 = x(2,2)-x2(nx2) ;
    l = sqrt(dx1^2 + dx2^2)*7.5 ;  % Scale the arrows
    if l > 1.e-10
      x1m(nx2,nx1)=dx1/l ;         % Notice the reversed indexes
      x2m(nx2,nx1)=dx2/l ;
    end
  end
end
quiver(x1,x2,x1m,x2m,0) ;
axis([-2.5,2.5,-2.5,2.5]) ;
xlabel('x1') ;
ylabel('x2') ;
grid ;