uwbmodulation.m

来自「该程序仿真超宽带的脉冲位置调制。是在MATLAB下实现的。」· M 代码 · 共 73 行

function [sys,x0,str,ts] = UWBmodulation(t,x,u,flag,A,tau,Tf,Tc,delta,xini,bitsPerHop)

switch flag,

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

    sizes.NumContStates  = 0;
    sizes.NumDiscStates  = 6;
    sizes.NumOutputs     = 1;
    sizes.NumInputs      = 1;
    sizes.DirFeedthrough = 1;
    sizes.NumSampleTimes = 1;   % at least one sample time is needed

    sys = simsizes(sizes);
    
    x0  = [xini 0]; % State of the state register and initial c0, m=5
    str = []; ts  = [0 0];

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

  %%%%%%%%%%
  % Update %
  %%%%%%%%%%
  case 2,
      x(6)=0;
      if abs(round(t/Tf) - t/Tf) < 1e-8
          for cnt=bitsPerHop-1:-1:0
              feedback=mod(x(2)+x(5),2);
              x(6) = x(6) + x(5)*2^cnt;
              for k=5:-1:2
                  x(k)=x(k-1);
              end
              x(1)=feedback;
          end
          sys=x;          
      else
          sys=[];
      end

  %%%%%%%%%%%
  % Outputs %
  %%%%%%%%%%%
  case 3,
    tmod=mod(t,Tf);
    sys = scholtzValue(tmod,A,x(6)*Tc+u*delta+2e-9,tau);

  %%%%%%%%%%%%%%%%%%%%%%%
  % GetTimeOfNextVarHit %
  %%%%%%%%%%%%%%%%%%%%%%%
  case 4,
      sys=[];

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

end