integratesample.m

该程序仿真超宽带的脉冲位置调制。是在MATLAB下实现的。

function [sys,x0,str,ts] = IntegrateSample(t,x,u,flag,SampleTime)

switch flag,

  %%%%%%%%%%%%%%%%%%
  % Initialization %
  %%%%%%%%%%%%%%%%%%
  case 0,
    sizes = simsizes;

    sizes.NumContStates  = 0;
    sizes.NumDiscStates  = 3;
    sizes.NumOutputs     = 1;
    sizes.NumInputs      = 1;
    sizes.DirFeedthrough = 0;
    sizes.NumSampleTimes = 1;   % at least one sample time is needed

    sys = simsizes(sizes);
    
    x0  = [0 0 0]; % Output, Subtotal, Present time
    str = []; ts  = [0 0];

  %%%%%%%%%%%%%%%
  % Derivatives %
  %%%%%%%%%%%%%%%
  case 1,
    sys=[];

  %%%%%%%%%%
  % Update %
  %%%%%%%%%%
  case 2,
      sys=x;
      if abs(round(t/SampleTime) - t/SampleTime) < 1e-8
          sys(1)=x(2); sys(2)=0;
      else
          sys(2)=x(2)+abs(t-x(3))*u;
      end
      sys(3)=t;
      
  %%%%%%%%%%%
  % Outputs %
  %%%%%%%%%%%
  case 3,
      
      sys = x(1)<0;

  %%%%%%%%%%%%%%%%%%%%%%%
  % GetTimeOfNextVarHit %
  %%%%%%%%%%%%%%%%%%%%%%%
  case 4,
    sys=[];
    
  %%%%%%%%%%%%%
  % Terminate %
  %%%%%%%%%%%%%
  case 9,
     sys=[];
     
  %%%%%%%%%%%%%%%%%%%%
  % Unexpected flags %
  %%%%%%%%%%%%%%%%%%%%
  otherwise
    error(['Unhandled flag = ',num2str(flag)]);

end