ppmtemplategen.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] = PPMTemplateGen(t,x,u,flag,pulseType,tau,Tf,Tc,delta,M,link,dataOnState,bitsPerHop,Ts)

global UWB_SIG_DETECT_ON;
global ACQUISITION_ON;
global ACQ_FRAME_TIME ACQ_REGISTER_STATE;
global DATA_ON DATA_ON_STATE_TIME;

switch flag,

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

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

    sys = simsizes(sizes);
    
    x0  = [zeros(1,5) 0]; % State of the register(m=5) and time hopping unit c
    str = []; ts  = [0 0];

    DATA_ON=0;
    DATA_ON_STATE_TIME=-1;
    
  %%%%%%%%%%%%%%%
  % Derivatives %
  %%%%%%%%%%%%%%%
  case 1,
    sys=[];

  %%%%%%%%%%
  % Update %
  %%%%%%%%%%
  case 2,
      if ACQUISITION_ON>0 & abs(round((t-ACQ_FRAME_TIME)/Tf) - (t-ACQ_FRAME_TIME)/Tf) < 1e-8
          if abs(t/ACQ_FRAME_TIME-1) < 1e-8
              initialState=ACQ_REGISTER_STATE;
              for k=1:link
                  [initialState,nextC]=nextState(initialState,bitsPerHop);
              end
              x(1:5)=initialState;
          end
          [state,nextC]=nextState(x(1:5),bitsPerHop);
          x(1:5)=state; x(6)=nextC;
          if state==dataOnState'
              if DATA_ON==0
                  disp('Data Synchronized.. Demodulation begins.');
                  fprintf('Demodulation Start Time=%5.3f ns\n',t*1e9);
                  DATA_ON=1;
              end
              DATA_ON_STATE_TIME=t;
          end
      end
      sys=x;
                  
  %%%%%%%%%%%
  % Outputs %
  %%%%%%%%%%%
  case 3,
      if ACQUISITION_ON>0 & t>ACQ_FRAME_TIME
          A=1; %Unit energy
          tmod=mod(t-ACQ_FRAME_TIME,Tf);
          
          temp=zeros(M,1);
          switch pulseType,
          case 'Gaussian',
              for k=0:M-1
                  temp(k+1) = gaussValue(tmod, A, x(6)*Tc+k*delta+floor(2*tau/Ts)*Ts,tau);
              end
          case 'Gaussian 1st Derivative',
              for k=0:M-1
                  temp(k+1) = gauss1stDevValue(tmod, A, x(6)*Tc+k*delta+floor(2*tau/Ts)*Ts,tau);
              end
          case 'Gaussian 2nd Derivative',
              for k=0:M-1
                  temp(k+1) = scholtzValue(tmod, A, x(6)*Tc+k*delta+floor(2*tau/Ts)*Ts,tau);
              end
          case 'Manchester',
              for k=0:M-1
                  temp(k+1) = manchesterValue(tmod, A, x(6)*Tc+k*delta+floor(2*tau/Ts)*Ts,tau);
              end
          case 'Sine',
              for k=0:M-1
                  temp(k+1) = sineValue(tmod, A, x(6)*Tc+k*delta+floor(2*tau/Ts)*Ts,tau);
              end
          case 'Rectangle',
              for k=0:M-1
                  temp(k+1) = rectangleValue(tmod, A, x(6)*Tc+k*delta+floor(2*tau/Ts)*Ts,tau);
              end
          otherwise
              error('Unsupported Pulse Type');
          end
          sys=temp;
      else
          sys=zeros(M,1);
      end

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

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

end